Leo is a jaded old lizard with a heart of gold who’s been stuck in the same Florida classroom for longer than he can remember, alongside his terrarium-mate Squirtle the turtle. He’s watched generations of students come and go, but feels like he’s missed out on life. When Leo learns he only has one year left to live, he plans an escape to experience life on the outside once and for all. Instead, he gets caught up in the problems of his anxious students — and an impossibly mean substitute teacher.