While floating down the Dark River, Ollie, Zozo and Rosy search for the next spot on Ollie's map. Ollie recalls something important about Momma.

The friends' quest takes a heavy turn as a heartbreaking flashback reveals how Zozo met Nina, then lost her. But a happy memory sparks much-needed hope.

Ollie remembers what happened on the last day he saw his best friend. Will he find his way home to Billy - or is he too late?