House and the team encounter a teenager who collapsed during her high school Christmas program. They soon find the troubled teen dealt with more than her share of bullying at school, and as her condition continues to deteriorate, the team must delve deeper to get to the bottom of her mysterious illness. Foreman continues to work with Thirteen on the Huntington's disease drug trial, and their relationship progresses when he learns a valuable lesson from her. House gives a clinic patient an unbelievable holiday gift and keeps the team guessing about who may have sent him a particularly thoughtful Christmas present. Meanwhile, Cuddy receives an unexpected gift of her own.
The BAU tries their luck in Atlantic City when the team is called in to investigate a series of ritualistic casino-related murders. Also, after a spat with her boyfriend, Kevin, Garcia thinks she and Morgan may have gotten a little too friendly with each other. Dean Cain Guest Stars as Down-On-His-Luck Gambler Curtis Banks.
Sarah, John and Cameron track down another name on their list and wonder why a T-1001 would need a doctor. Meanwhile, a woman from Derek's past surprises him in the present.
