Sonic the Hedgehog (OVA)

Past
Sonic has spent his whole life in the Land of the Sky, never setting foot in the Land of Darkness. He lives with his best friend, Miles "Tails" Prower, on their own small continent. During their time, Sonic and Tails served as the defenders of South Island, protecting it from the evil Dr. Robotnik, who sought to dominate all of Planet Freedom. The two of them would also work closely together with the President in their heroic efforts.

Over the time, Sonic fought Dr. Robotnik countless times to stop his evil plans. At some point, Sonic became friends with Knuckles the Echidna, and they have known each other for a while.

Welcome to Robotropolis
At the beginning of Sonic the Hedgehog: The Movie, Sonic was relaxing at the beach near his home, when Tails came out to reveal his new jet-propelled surfboard and offered Sonic to give it a try, but Sonic declined. As Tails tested out his new invention, Sonic tried to resume his relaxation and to listen to the radio, but got splashed from the surfboard's waves a couple of times. As Sonic declined another offer from Tails to try out his surfboard, Sonic tried to relax again, but then heard Tails shouting. Deeming it nothing to worry about, Sonic tried to ignore it, but as Tails continued to call for help, Sonic finally had enough and told Tails to shut up, only for then to notice that an airplane was on a collision course with him. Sonic managed to avoid the plane in time, however, and assured Tails that he was fine. Sonic then noticed, much to his own dismay, that it was Old Man Owl flying the plane, and decided not to get involved, even though his small aircraft began to fail and had caught on fire. Tails tried to convince Sonic to help him, but Sonic told him that he could do it, to which Tails said that Sonic was no help and tried to do alone. As Sonic was resetting his sun bed and parasol, however, he heard Tails' cry for help and hurried out, and managed to save both Tails and Old Man Owl seconds before the airplane impacted the cliff's side.

Once on safe ground, Sonic and Tails heard from Old Man Owl that the President wanted them to come to the Presidential house, though Sonic remarked that he could just have called them. Boarding the Tornado, Sonic and Tails took off to the Presidential house to answer the call, though not before Sonic told Old Man Owl to watch their home while they were gone (although Sonic had his doubts about that).

Once inside the Presidential house, however, Sonic and Tails found Dr. Robotnik waiting for them and he attacked them with his robots, but Sonic and Tails quickly dispatched them. As Sonic moved in to attack Robotnik, however, he was forced to stop when he noticed that Robotnik held the President and Sara hostage with his guard robots. Robotnik then told Sonic to listen to him as he had information that concerned the entire Planet Freedom, but Sonic refused to listen. As Robotnik threatened to kill Sara and the President pleaded for Sonic to listen, he agreed to.

Robotnik explained to them that a robot called Metal Robotnik had appeared, taken over his home in the Land of Darkness, Robotropolis, and had sabotaged the Robot Generator to run out control, which would eventually explode by sunrise tomorrow and destroy the entire Planet Freedom, but Sonic and the rest eventually fell asleep during the doctor's explanation. After awakening them, Robotnik said that the only thing to do was for have Sonic infiltrate Robotropolis and turn off the Robot Generator, as he was the only one fast enough to do it. Sonic, however, refused to clean up Robotnik's mess, as he had his firm doubts about trusting the doctor. However, after being persuaded by the others, Sonic finally agreed to do it. After receiving a navigator from Robotnik, Sonic and Tails headed out in the Tornado to Robotropolis.

While en route to Robotropolis, Sonic asked Tails if they could trust the navigator Robotnik gave them, as he feared it could contain a bomb, but was told by Tails that they had no other choice than to trust it. Eventually, Sonic and Tails found the storm-like entrance to the Land of Darkness. As they descended through the entrance, Sonic was nearly blown off the Tornado by the strong winds, but managed to hold on until they reached the surface, where they crash landed. After seeing that Tails was fine, Sonic looked with awe at the unknown lands they had arrived in. As Tails determined their traveling route, Sonic and Tails headed to Robotropolis on foot. As Sonic raced through the vast landscapes, while avoiding traps and destroying Badniks, Sonic began to suspect that Robotnik had picked the route with the most traps for them. Sonic and Tails eventually reached a warp zone, where Sonic accelerated to top speed as they passed through it, eventually reaching the ruins near Robotropolis.

Seeing the devastation brought by the Robot Generator's destabilization, Sonic and Tails hurried through the ruins, but they were suddenly attacked. The attacker revealed himself to be Metal Robotnik, but Sonic dismissed the metallic giant, telling it that they did not have the time for this. Metal Robotnik still attacked them with gatling guns, but Sonic and Tails managed to avoid its attacks. The robot's armor, however, proved to be too strong for Sonic to break through. Realizing that they did not have time to fight such an opponent, Sonic had Tails pinpoint the way to Robotropolis. The duo then tried to escape Metal Robotnik, to which Sonic taunted Metal Robotnik by saying that they would finish it when they came back, but Sonic and Tails were surprised when Metal Robotnik took flight and pursued them.

In the ensuing chase, Sonic and Tails nearly fell into the ocean below a bridge due to Metal Robotnik's missiles. As Metal Robotnik shot them down from the bridge, Sonic and Tails made it sound as if they had drowned in order to trick Metal Robotnik. As they tried to sneak away, however, Metal Robotnik ambushed them and tried to trap them with superglue-like bombs. As Sonic saw Tails being trapped, he was targeted by some of Metal Robotnik's missiles, but Sonic managed to ride one of them back and hit Metal Robotnik with it, before jumping off. Unfortunately, Sonic landed in one of the superglue-like bombs, which kept him stuck to the pavement. Sonic then saw that Metal Robotnik had survived and was approaching him, with its massive weight causing the pavement to crack and Sonic to sink into the water with it.

Before Sonic could get killed by Metal Robotnik, however, Knuckles appeared to fend off the attack. Sonic was then saved by Tails, who got him out of the water before he could drown, and Sonic managed to save Knuckles from being crushed by Metal Robotnik by cutting the robot giant's hand off. Metal Robotnik then tried to escape, but Sonic would not let it. With Knuckles' and Tails' help, Sonic managed to finally penetrate Metal Robotnik's armor, before cleaving it in half, seemly destroying Metal Robotnik for good. After the battle, Sonic thanked Knuckles for his help, but the reunion was cut short as they saw the sun was about to set. Fortunately, however, Sonic and Tails also saw that Robotropolis was within plain sight, which Sonic thought looked eerie. With not much time to waste, Sonic told Knuckles that he hoped that they would see him again soon before heading out but Knuckles decided to join Sonic and Tails.

Sonic Vs. Metal Sonic
At the entrance to Robotropolis, Sonic, Knuckles and Tails hurried into the center of Robotnik's massive base. On their way, the group was attacked by Badniks, but thanks to Knuckles' back-up, Sonic and Tails could hurry unconcerned to the Robot Generator. As they duo finally found the Robot Generator, which was only seconds away from exploding, Sonic and Tails was caught on a treadmill, halting their advance. Running with more effort than ever, Sonic overcame the treadmill and managed to shut down the Robot Generator in the nick of time, but then found himself caught in an electrifying green energy field, unable to escape. The Robot Generator then fell apart, and Sonic was released, falling stunned towards the ground, but was saved by Knuckles. As he came to, Sonic, Tails and Knuckles witnessed a sphere in center of the Robot Generator which had something moving inside. As the sphere exploded and the dust cleared, Sonic was shocked when he suddenly found himself standing face-to-face with a robotic twin, called Hyper Metal Sonic.

Suddenly, however, the group heard Metal Robotnik's voice and saw the remains of Metal Robotnik rising from the ground, for then to see it fall into pieces. The group were confused as they heard voices coming from the rubble, and Sonic was left dumbfounded when he saw Dr. Robotnik and Sara emerge from the remains. Sonic demanded Dr. Robotnik to tell him what was going on, and Robotnik revealed that Metal Robotnik and the Robot Generator was all a trick on his behalf to get Sonic to Robotropolis. In a fit of rage, Sonic charged at Robotnik, but found himself blocked by the surprisingly fast Metal. Dr. Robotnik then introduced Metal to Sonic as the doctor's invention, and revealed that the green energy field that Sonic was caught in earlier downloaded his life data into Metal in order to make him the ultimate fighting machine that would allow the doctor to finally kill Sonic and destroy the Land of the Sky. Sonic angrily told Robotnik to release Sara, but the doctor said that he first had to fight Metal.

Feeling that defeating his robotic double was his duty, Sonic confidently told Tails and Knuckles to stand down and let him fight his imposter alone. After avoiding Metal's initial charge, Sonic began a battle at incredible speeds with Metal, but soon found himself on the ropes as Metal proved himself as an incredible opponent, matching him blow for blow. After being briefly knocked by Metal, Sonic was dragged to the mountains where his following fight with Metal tore mountain tops apart. Unable to lay a solid blow, and eventually losing sight of Metal, Sonic looked around for his metallic double, but received a surprise attack from above, knocking Sonic off the mountain peak down to the landscape below.

While Sonic was believed to be dead, however, he managed to survive the fall. The following morning, he woke up in a forest, trying to remember how he ended up there. In the process, Sonic had a vision of Metal destroying South Island, as they shared the same personality and memories (thus creating a mind-link between them), and Sonic resolved to find Metal and stop him. Sonic eventually made it back to the Land of the Sky, where he eavesdropped on Knuckles' conversation with the President over the intercom. During the conversation, the echidna deduced that Metal's next target would be the glacial bridge at the northernmost tip of the interconnected continents. If this was destroyed, the Land of the Sky's continents would be hurled into space due to the centrifugal force of the planet. Sonic then revealed himself to the group, and stated that he intended to fight Metal. When Sonic heard that Metal was heading north, Sonic rushed off to stop the robotic hedgehog.

Sonic eventually made it to the glaciers, but saw that he arrived too late as Metal had already released some magma pockets. As he stood thinking of what to do, Sonic saw Metal emerge from below his feet, but managed to avoid him. Face to face with Metal, Sonic announced that this would be the real fight between them and that the "last Sonic standing would be the winner". Metal, however, announced this was a battle for their lives, as there could only be one Sonic in the world. Sonic agreed on terms, and Sonic clashed with Metal in a long and intense battle between two opponents of equal might.

As explosions erupted from the collisions between them, it became apparent to both Sonic and Metal that they could predict the other's actions move for move due to them sharing the same thoughts, and as such, neither of them could gain the upper hand on one another, to which Sonic replied was "strange". Their battle was temporarily interrupted by the untimely arrival of Dr. Robotnik and Sara, as they crash into the Egg Mobile, with Sonic landing on the top and hurting his groin, but Sonic quickly recovered to resume his fight and accidentally freed Sara from Robotnik in the process.

The battle between Sonic and Metal became increasingly fiercer as the two of them literally tore the icy wasteland apart in the wake of their fight, with Sonic receiving some solid blows from Metal and otherwise, but they could still only fight to a stalemate. Sonic, however, slowly became more and more exhausted from their prolonged battle, thus allowing Metal to grab Sonic in a chokehold. Before he could get killed, however, Sonic was saved by Tails who managed to overload Metal's system with the Navigator, paralyzing him. Sonic then took the opportunity and hit Metal directly with a powerful Spin Dash, sending him flying into the horizon.

After thanking Tails for saving them, Sonic saw that the President and Old Man Owl had crashed into the glacial bridge in the President's personal ship, which was about to explode. As Sonic was carried by Tails up to save the President, however, they were attacked by Metal again. Struggling back onto his feet, Sonic told Metal to stand aside, but was denied by his robot twin. Tails tried once more to overload Metal's systems, but was stopped by Dr. Robotnik, which led to Sonic engaging Metal again. Despite receiving some blows, Sonic eventually managed to gain the upper hand on Metal and overwhelm him, and he knocked him into the President's ship and defeating him, causing it to explode. Exhausted, Sonic ran to the wreckage to find the President, but was surprised to see that Metal had saved the President and Old Man Owl, before dropping them on him.

To his shock and horror, Sonic saw Metal being knocked over by debris into a pit filled with rising magma. Sonic, seeing that Metal Sonic had some good in him, like himself, jumped into the pit, sliding down the side, to try and save the incapacitated Metal. Despite Knuckles trying to stop him, Sonic reached out his hand to grab Metal, but was confused as Metal slapped it away. Sonic then heard Metal's thoughts, which said "There is only one Sonic...", and was forcefully restrained by Knuckles as he watched Metal melt away into slag.

In the aftermath, Sonic was mourning Metal's death and was lost in thoughts, but was snapped out of them when Dr. Robotnik appeared and announced that he would build a superior Metal Sonic, as he still had the CD containing Sonic's life data. Fortunately, the CD was blown up by one of Dr. Robotnik's faulty missiles, to which Sonic joined the others for a laugh. Sonic then received a hit from Knuckles, as payback for stepping on him while fighting Metal, and Sonic chased after him, arguing with him that he did not remember doing that. As Sonic ran after Knuckles, he saw everyone approaching him in the Egg Mobile, each chasing after him for their own reasons. Sonic then told Knuckles that he was getting out of there, and raced away.