Undergrounded

Peter secretly gets a credit card after running out of cash at the Drunken Clam at the encouragement of the guys. After going on a spending spree, Lois grounds him for acting like a child. Desperate to escape the house, he builds a tunnel all the way to the Clam. When he shows off his handiwork to the guys, they end up trapped when the tunnel collapses.

Afraid that they may run out of air before being found, Peter confesses that their only hope is that Brian rats them out to Lois. The former lies to her about where Peter is, but tells Stewie who manages to trigger enough clues to locate them. While passing the time, they share secrets in their lives. The rescuers get them out and Lois rips into Peter for lying to her as he apologizes, but complains that she always treats him like a kid.

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In a flashback of Peter's secret of Lois killing a person during their honeymoon 20 years previously to close the episode, they are in a seaside cafe and Peter selects the waitress for assassination because the chef says he can't make a chocolate chip & gumball pizza as Lois pulls out a gun and tells Peter that she loves him so much.