You shouldn't take belongings that don't belong to you.
At the end of gym class, while Mike is in the bathroom, Jim notices there is a PSP in Mike's locker.
Jim wants to play the PSP.
When Mike returns, Jim asks Mike if he can play the PSP sometime.
Jim takes the PSP before Mike comes back.
Mike says he can play the PSP tomorrow and this makes Jim happy.
Someone saw Jim, reported Jim to the teacher and Jim got in trouble.