Two Old Men and a Lock is the 35b episode of middle season.
While searching for Bubbie's birthday present on an island, Flapjack and K'nuckles come across two old men named Richard and Michard, who were a captain and a boy who used to go on adventures together. Now they hate each other because Michard has a treasure chest and Richard has the key, and they won't share because they don't trust each other. Flapjack and K'nuckles make a plan to steal the treasure chest and the key. The plan works, but they end up fighting like Michard and Richard.
Michard and Richard unlike Knuckles and Flapjack.
"Two Old Men and a Lock Box" aired April 19th.