It's the holiday season and at a rock wall-climbing, a daughter Jane is ascending the wall as her mother Maggie encourages her. She slips and hangs, but Maggie's hands are paralyzed and she loses her grip on the safety line, causing Jane to fall and break her arm.
House's new team go over Maggie's case but House is less then thrilled that Kutner has put up Christmas decorations. Maggie has had breast surgery and Taub suspects they didn't get all of the cancerous cells. House suspects Maggie is a liar, but her record shows that she doesn't lie to people. He then talks to Jane, who confirms that her mother tells her everything and they don't lie to each other. House is shocked, believing everyone lies, and sends Taub and Foreman to talk to her last sexual partner, Roger. They trick him into revealing he gave her E to relax.
House sees a woman with a throat problem, Melanie, and talks about St. Nicolas while determining she has strep. He determines she's a prostitute but she comes on to him. Taub reports in to let them know they're testing the drug and Maggie's blood. However, she goes blind as Kutner runs drug tests.
On Cuddy's orders, House prepares the Secret Santa and amuses himself by watching their reactions. The E tests proves negative so he sends thirteen and Kutner to break into Maggie's house and computer, while Taub and Foreman run more tests to check for vascular problems suggesting angiogram and talk to her about her honesty. Wilson wonders why House is doing the Secret Santa and he explains about his theory on gift-giving pissing people off.
Kutner and Thirteen return, with Thirteen eager to prove House wrong. House goes over their computer while Foreman suggests she might have psych problems leading to a lack of inhibitions and excessive honesty. House wonders why Thirteen is protecting Maggie, figuring she's still lying about her own personal problems that House hasn't identified. They then go to Jane to convince her to lie to her mother about a placebo treatment they're giving her. Jane admits she knows how to lie… but won't lie to her mother. Taub prepares the "treatment" and they keep Jane away from her. The team figures out that House gave them all his name, while Taub monitors Maggie whose lymph nodes expand and cut off her airway.
They open up her airways with alcohol and conclude it isn't psychological, while Kutner notices House has a present on his desk. He concludes Maggie has sarcoidosis when he notices she sold her Stairmaster and canceled a hiking trip, going through her e-mails. House opens his present, an Apple iPhone. The team wonders who got House a present… while House returns it to Wilson, who he stole it from. Maggie tests negative for sarcoidosis but she starts bleeding out of the eyes. It's back to differential as they determine her platelets are breaking down. Kutner then notes that House is his Secret Santa and wonders who got House the present… and gives House a present as well.
Melanie comes back to visit House and reveals she has a rash on her neck. He determines she does a "donkey show" and gives her a prescription, and she offers him a ticket to her show. Meanwhile, Chase and Foreman prepare to drill into Maggie's skull but discover that the bone is harder then the drill. The team thinks Kutner ruined the test, but he defends himself. They run blood tests for the only thing that causes hardening of the skeleton that is curable: if it's positive, she'll need a bone marrow transplant. They prepare to test Jane for a match, although Maggie objects due to the risk and insists they find someone else to take the risk. Later, Taub reports to House they found a donor and gives House a present, but Thirteen reports the test proved negative so no donor is necessary. She then gives House his present from her, then refuses to get mad at Kutner to irritate House. Jane comes in and insists they test her morrow.
House talks to Maggie and tells her to give Jane one last present: the truth. House figures Maggie refused to do the donor test because Jane isn't really her mother. Maggie finally admits to House she adopted Jane from a drug addict and promised never to say. However, when Jane comes in she finally refuses to tell her adopted daughter the truth… and Jane tells her the truth, that she's dying.
House goes out past the hospital party but runs into Wilson and admits he was impressed with the truth telling. Getting an idea, House meets with his team while he carols, and tells them to give Maggie an anti-psychotic. House explains that a bit of her breast cancer detached and got into her bloodstream, and the anti-psychotic will cause it to swell. He finds the swelling on the back of her knee: they can cut out the tumor and put her on chemo to cure her.
Later everyone gathers for the staff party… except House, who walks out, alone. He then goes to church where Melanie is performing as the virgin Mary in a nativity scene, riding a donkey.





