What happens in Sonic the Hedgehog the movie?

Answer 1

in a nutshell;

Sonic and Tails are playing at the beach by their house. an old man (that's his name) an owl... tells them that the president of planet freedom needs them. they go, and as it turns out, Robotnik is holding he and his daughter, Sara, captive. Robotnik tells a story of 2 dimension of the planet: the Land of the sky (LOS), and the land of darkness (LOD). he used to live in Robotropolis, in the LOD , until Metal Robotnik fought him away. after which, he sabotaged the generator for the city, which runs excessively and has no storage outlets, presuming a massive explosion, capable of destroying the planet. Sonic, being the "only one" fast enough, refuses to go, but is convinced by Tails and Sara. Robotnik gives Tails a navigator to Robotropolis.

there's only one way to get to the LOD, and Ssonic and Tails take the tornado to get there. once in, they find a ruined city, which are known as the ancient relics, even though it included functional traffic lights. there, they met Metal Robotnik. fighting with all he had, he could not catch Sonic and Tails. they eventually escape his range, but he reveals a very fast rocket on his back and chases them down a highway toward Robotropolis. revealing a sticky substance, he sticks Sonic and Tails for capture, when Knuckles saves Tails to help Sonic while he himself fights Metal Robotnik. after pulling Sonic out of the icky stuff, they defeat Metal Robotnik with Sonic's spindash. (which simultaneously reveals Knuckles can fly freely like they do in DBZ).

Knuckles lets Sonic and Tails continue on their way, as time is short. but he decides to come along after a minute. once there, they must fight many robots that are seen in the original games, such as the buzzbombers. reaching the generator, they run into a massive treadmill that goes even faster than Sonic. shutting it down with .01 seconds left, Sonic is electrocuted, apparently. Tails examines that it doesn't look right, though. it shatters. inside is found a robot that looks like Sonic.

Metal Robotnik, destroyed, returns like a ghost, but is revealed to be carried by functional robots, and then also shatters, with Robotnik and Sara inside. revealing his plan, Metal Sonic was JUST finished when Ssonic seemed electrocuted, but was actually scanned. Metal Sonic knows every last thing Sonic does. no more or less. planning to destroy the LOS, Robotnik commands Metal (his nickname) to destroy Sonic. with eruptive combat, Sonic and Metal seem very even. Tails and Knuckles panic, not knowing how to help, as they are too slow. Metal eventually wins, high above the city, as he can fly. Sonic seems dead, but is not hunted for proof.

Tails, convinced, drags Knuckles and goes home. they get a call from the president saying that Sonic has been destroying cities and landscapes. they tell him it's a robot, and Knuckles, being a treasure hunter, tells that there's one point in a polar region where the LOS and LOD are connected, and without it, the LOS will fling into space and crumble, making it Metal's target. Sonic, overhearing the conversation, goes after Metal. by the time he arrives, he's late, but not too late. in decent conversation he and Metal conclude there is only one Sonic. He fights Metal brutally, pieces flying and bruises showing. Knuckles, Tails, Sara, and Robotnik show up, and cheer. Knuckles starts digging ways for the destructive magma to flow so it doesn't reach the connecting point. Tails, having hacked the navigator, has some control over Mmetal, and exponentially increases the personality Sonic has. using the opportunity, Sonic strikes him for good. beaten, Sonic sees the president crash into a glacier, near the magma. Metal returns, and for some reason, saves the president when the engine explodes. a piece of the ship falls onto Metal, and kknocks him into a hole, leaving him broken by the lava. Sonic attempts to save him, but Metal refuses, speaking in English for the first and last time, "There-is-only-one-Sonic". Sonic, glum, is cheered up by Sara and Tails. Knuckles hits Sonic's head, because he jumped on Kknuckles for leverage during his fight without noticing. (in the movie, Knuckles is a mole 0_0)

Sonic chases Knuckles for doing that, and the rest of the characters follow. Sonic, annoyed, decides to forget Knuckles and bullets ahead, into the camera, and his name is typed out. credits roll.