If Journey to Eternity and the enchanted creature are both put into graveyards at the same time, Journey to Eternity's ability will return both to the battlefield.

If Journey to Eternity enchants a creature you control but don't own, the creature will return to the battlefield under your control from its owner's graveyard when it dies. In a multiplayer game, if a player leaves the game, all cards that player owns leave as well. If you leave the game, any creatures you control from Journey to Eternity's effect are exiled.

If another player gains control of the enchanted creature, Journey to Eternity will be put into your graveyard.