While Marge, Bart, Lisa and Maggie have an awkward, uneventful visit with Grampa, Mason and Homer are underwater in individual submarines looking for the lost treasure. Homer gets separated from Mason, and he follows a small light, thinking it is him. It is actually a glowing fish, and Homer gets stuck in some coral. As his oxygen begins to run out and he starts to lose consciousness, he sees poignant flashbacks of himself and Abe. After three days in a coma, Homer wakes up in a hospital, tells Abe of his memories, and says he considers Abe his real father. Abe then reveals he switched the labels on the DNA samples after seeing how happy Homer was with Mason and the fully confirmed biological father-son duo share a hug.