New friends Sika and Shen try to beat the odds and win the Great Northern Race--in a sled pulled by a team of sixty-six pugs--in hopes of meeting the Snowfather and having him grant their wish.

Reports of a strange phenomenon at the fringe of the galaxy and its connection to one of Father's old friends send the entire Mumby family, accompanied by Jack and other friends, to a far-off planet where they must find a way to prevent a new invasion of the solar system by giant moths.