Grunkle Stan is forced to reveal his history with his twin brother to Dipper and Mabel.
After government agents take him into custody, the twins uncover some things that cause them to question how much they know about their Grunkle Stan.
Dipper tries to rid the Northwest Mansion of a ghost before it wreaks havoc on Pacifica's upcoming party.
At a family Christmas party, Bob and his father, "Big Bob," revisit an old argument, which leads to a can-you-top-this competition in the kitchen. Meanwhile, the kids compete to come up with the perfect gift for their dad.moreless
The CIA showing up during the Mystery Shack's re-opening leaves Stan feeling threatened; that is until he's faced with an even greater threat: zombies!