The Secret Life of Sam [Ventrella, Kim]

When Sam's dad dies in a car accident, Sam is shuttled off to the dusty town of Holler, Oklahoma, to live with a long-lost aunt. There he encounters a mysterious mangy cat who leads him to an unassuming tree that turns out to be a portal--a passage through which Sam can revisit his old life for a few minutes at a time.

Sam's visits to the bayou become stranger and stranger. Pa's old stories unfold around him in beautiful but sinister detail, and Pa is not quite himself. Still, Sam is desperate to find a way for them to stay together--no matter what it takes.