Leo has been stuck in the Prison Dimension with the kraang for 8 months. He had no memory of his brothers or sister. When he came out of the Prison Dimension, he couldn't speak right, he only said, "Treasure" and "My sanity". Mikey just got Leo out

Mikey: "Leo!" Mikey hugs Leo tightly

Raph, Donnie, and you hug your brother. Leo looks very confused. He chrips a bit. Leo wasn't the same at all. Casey, April, and Splinter get to the turtles location and hug Leo tightly