Several years back, Milo and Spencer's grandfather, Eddie Gilpin, owned a restaurant together, called “Milo and Eddie’s”. Milo later retired after 15 years and sold it to the new manager, Nora Shepherd, which caused a rift between him and Eddie. Several years later, Milo discovered he had an unspecified illness, and doesn’t have a lot of time left. He then visits Eddie, who is staying at his grandson Spencer's home, to try and make amends, even though Eddie doesn't want to. Later, Fridge, Martha, and Bethany arrived to try and find out where Spencer was and the three were introduced to Milo, who recognized Fridge from when he and Spencer were kids.
When the three decide to go into Jumanji to find Spencer, the malfunctioning game system also sucked in Eddie and Milo, Milo was placed into the body of Franklin "Mouse" Finbar. However, he was not very good in the role, as his casual attitude kept him from revealing key info in a timely manner, which ended up costing lives during the journey.
He and Eddie kept arguing during the game, but they eventually reconcile and Milo reveals his reason for wanting to restore his friendship with Eddie. After discovering a pool of water that will allow them to switch avatars, Milo is placed into the body of the horse, Cyclone, and discovers he possesses the ability to fly with wings.
At the end of the adventure, Milo decided to stay behind and protect Jumanji, sharing a heartfelt good-bye with his best friend, he then ran off and flew into the air.