Digimon Xros Wars
Mikey Goes to Another World
S1 E1:
Mikey, an upbeat seventh-grader who can't resist helping people in trouble, encounters a Digimon named Shoutmon, who brings him and his friends to the Digital World in order to save it from the Bagra Empire. Once they realize they are no match for MadLeomon, they are joined by a handful of others to help them succeed in their mission.