David and Jenny's romantic night is thrown into disarray by Gregg's scheming and Harvey's garage band practice.

When Jenny's mom invites the Langers to dinner, David claims that the others are out of town so he can go by himself, which backfires spectacularly.

Gregg disrupts David's train of thought just when he is on the verge of cracking the most famous unsolved math problem, so the family teams up to get him back on track.