Ding, dong! Penny and Amy are ready to party!
Penny accompanies Amy to a "party" hosted by Bert (Brian Posehn), a geologist, while their other halves find themselves stuck at work. As Bert strokes the girls' egos, tensions rise between Sheldon, Leonard, and Howard, who struggle to complete their government project on time.
Meanwhile, Raj learns Bernadette's true feelings about her pregnancy when they clean out the baby's room on the latest episode of The Big Bang Theory called "The Dependence Transcendence."
Watch The Big Bang Theory on Mondays at 8/7c on CBS and CBS All Access.