Sonic the Hedgehog 2

Robotnik gets rescued from the mushroom planet by Knuckles, who is after Sonic because he thinks Sonic is hiding the Master Emerald, which he makes the mistake of mentioning is incredibly powerful while standing within earshot of Robotnik. Cue super-villain team-up, with inevitable betrayal.

Meanwhile, Tails showed up because he somehow picked up on Sonic's energy when he caused the blackout early in the first movie. He saw Sonic be a hero, and basically showed up up to fanboy. It's a weird mix of tones in this movie. You have Sonic making a huge mess when he's left home alone, and another sequence where he and Tails go to a bar and get into trouble. Siberian dance-off trouble.

At the same time, Knuckles is there as possibly the last member of his people, trying to retrieve the Emerald Sonic's giant owl mother and her people hid (because it's immensely powerful and dangerous). So Knuckles' people are responsible for killing Owl Momma, and she is quite likely responsible for killing Knuckles' father. And now the kids are fighting each other. Sonic's getting punched through walls, he does the spinning dash things and drives Knuckles through solid rock. It's not like there's blood or dismemberment or anything, but definitely a couple of characters working through abandonment by whupping the shit out of each other.

And in the midst of all this, James Marsden and Tika Sumpter are playing Sonic's adoptive parents, who got to Hawaii for Sumpter's sister's marriage. The sister, Rachel, still doesn't like Marsden's character, so of course he messes up her wedding. Even those low-scale hijinks then get roped into the fact that Robotnik originally came after Sonic at the government's behest. 

That part fits awkwardly with the Emerald stuff, but I think they wanted to make a point about how Sonic found a new family, which he adds to with Tails and Knuckles, but they didn't have a good way to incorporate Marsden and Sumpter's characters into the Emerald hunt. So the movie tries to give them something else to do until they can be involved.

Jim Carrey's still bringing a lot of energy, which is good since he interacts with CGI talking animals roughly 90% of the time. My favorite bit was when he yells that he can't die from being run over by a giant spiked boulder because it's too derivative. That or when he criticizes Stone for not having read the manual (of the giant robot he just created), and a few minutes later, Stone uses a weaponized mustache. When Robotnik asks what the hell that was, Stone holds up the manual. He works for a lunatic, but Stone is a devoted employee.