How Lily Stole Christmas is the first Christmas episode of How I Met Your Mother.
It's Christmas time in The Apartment and the whole room is full of festive decorations. Marshall is heading to the law library to work on a report. He leaves with his hands over his eyes claiming that Lily's "Winter Wonderland" is his reward for a job well done.
Lily comes across the old answering machine for the apartment. She and Ted find few messages remaining on the machine. One message was for Marshall, recorded by Ted when the former was still pining over Lily who had left him:
"Hey, Marshall, are you lying on the couch right now moping about Lily? You are, aren't you? Well, stop it! She's not worth it. You gotta get over that grinch!" Future Ted clarifies that he had not in fact used the word "grinch." Instead, he said "a bad word. A very, very bad word."
Lily is horrified. She demands to know how Ted could say such a thing. Ted struggles to explain that he had been desperate to get Marshall out of his slump during Lily's absence. He had tried to help him get over it by knocking her off the pedestal Marshall kept her on. He claims he was merely doing his duty as Marshall's best friend.
Down at the bar, Ted recounts all this to Robin and Barney. Robin says that at least he apologized but Ted admits that he had not apologized to Lily. Instead, a fight broke out. Ted maintained that he was only trying to help Marshall after Lily left. In fact, he even states that he won't apologize because that summer she had been a "grinch". Lily says that he will be sorry.
During Ted's conversation with Barney and Robin, it becomes apparent that Barney has a cold. He denies it but fails at picking up a girl when he sneezes all over her.
Ted, Robin and Barney head upstairs with Barney continuing to deny that he is sick. Ted has a mug of beer in hand. He explains to Robin that the beer was an offering he used to make back in college when the two were fighting. However, when they enter the apartment they find that all of "Winter Wonderland" is gone. Lily stole Christmas!
Robin tries to convince Barney that he belongs home in bed after finding him attempting to smoke a cigar out on the fire escape. He is vehement in his assertions of health. Ted gets Lily on the phone and learns that she has taken the decorations to her apartment. She explains that she would deal with a foul-mouthed student by calling their parents. But Ted should know better. She hangs up before Ted can finish demanding she return the decorations. Ted heads out to the Bronx to confront Lily at her apartment.
On the way he speaks to Marshall who is excited about the Winter Wonderland and then is interrupted by a call from his mother who is angry about Ted's bad language. Meanwhile, Robin has convinced Barney to rest in Ted's bed. De-suited, he is miserable about his predicament but allows Robin to feed him soup.
Ted confronts Lily in her apartment which is cramped with the decorations. He begs Lily to come home. He apologizes for calling her "that word" but Lily says he is faking the apology and is still mad. She explains that she apologized to Marshall who has forgiven her and they have moved on. Why can't Ted? Ted admits that he is mad because she never apologized to him. Ted was upset with her for leaving him too. "We're supposed to be friends," he says. They start to argue and Ted calls her a "grinch" again. Ted says that she can return to the apartment because he won't be there and instead will be spending Christmas Eve with his cousin.
Marshall comes home with a package under his arm. Lily has returned the decorations leaving Marshall none-the-wiser. He tells her about the adventure he had getting her the package and then helping the delivery man bring presents to others throughout the day so people will have presents in time for Christmas.
The present is an Easy-Bake Oven. Lily is surprised because, while she had always wanted one as a child, she had never told Marshall. Marshall explains that the suggestion actually came from Ted. One night, back in college, Marshall had gone out; Ted and Lily were high and Lily told Ted about it. Lily is touched that Ted remembered the tidbit and suddenly feels guilty for forcing Ted to spend Christmas with his family.
Ted is on Staten Island spending Christmas with his pregnant, ultra-Christian cousin, Stacy, and her family. The doorbell rings and Ted finds Marshall, Robin, Barney and Lily holding a mug of beer. She and Ted exchange apologies and the gang heads home.