Adventure Time: Family Reunited

Before the Mushroom war, Carter, age 23, an eccentric uncle to a then young Marceline, he utterly adored her, and she adored him back, the pair were nearly inseparable. When the bombs began to drop, he took shelter in a hidden secret government facility underground and went into stasis. 996 years later whilst dungeon exploring, Finn and Jake accidentally unfreeze him and take him to the Mushroom Kingdom to help him recover with the help of Princess Bubblegum. Somehow by fate or destiny, Carter and a now 1003-year-old Marceline reunite, now Marceline helps Carter adjust to the new world he has now found himself in and to pick up for lost time.