At the funeral of their German-born grandfather Johann von Wolfhausen, brothers Jan and Todd Wolfhouse discover that family tradition demands that they travel to Munich on Oktoberfest to spread his cremated ashes at the Theresienwiese. There, the brothers unintentionally start an altercation that takes down an entire Oktoberfest tent. They then participate in Beerfest, an underground drinking game tournament run by Baron Wolfgang von Wolfhausen, where they discover that the von Wolfhausens are related to the Wolfhouses. The German team angrily denies the family ties, revealing that Johann was a stable boy who stole the recipe for "the greatest beer in all "ze" world" decades ago and ran away with his prostitute mother (the brothers' great grandmother), Great Gam Gam. Enraged by the mockery of their ancestors, Jan and Todd challenge the Germans to a drinking game. The brothers' defeat humiliates them in front of everybody, with Wolfgang pouring their grandfather's ashes on them and Jan getting punched in the eye.