Ted Mosby tells his kids the story how he met their mother, but he is tells it in very small bits - each week a different part of his past that inolves his best friends Marshall, Lily, Robin and Barney.
When the gang finds out that Barney and Robin are hesitant to define their relationship, Lily forces them to confront their biggest fear... becoming boyfriend/girlfriend. Meanwhile, Ted is anxious about teaching his first lecture.
Ted discovers he had been fixed up with the same woman, seven years earlier. The rest of the gang goes to the Lusty Leopard strip club and see a dancer who looks like Lily.
When Robin fears that Barney is cheating on her, she soon discovers that he is spending his evenings with Ted learning everything there is to know on how to date her. Marshall gives away a prized possession.
The Sexless Innkeeper
Marshall and Lily desperately try to have a double date with Barney and Robin. A girl falls asleep at Ted’s apartment after meeting him at the bar, making him the "Sexless Innkeeper".
Ted proposes a road trip with Marshall to their favorite pizza parlor in Chicago to reminisce their bachelor days, but Lily comes on the trip, spoiling the ’bro’ time. Barney is seeking American citizenship for Robin, but her Canadian traits still remain.
Barney, thinking he and Robin are the perfect couple, gives relationship advice to Marshall, which turns out to be a big mistake. Ted and Robin have some noisy neighbours.
The Rough Patch
Ted and Marshall decide to break Barney and Robin up for good after they hit a rough patch in their relationship. When their plan fails, they turn to Lily and she enlists some things to break them up, including Alan Thicke.
Barney pulls out all of his greatest tricks to reenter the dating scene after he and Robin break up with the use of the Playbook.
Slapsgiving 2: Revenge of the Slap
The gang celebrates Thanksgiving this year with Lily’s estranged father (Chris Elliott) whom she hadn’t spoken to in three years. Ted and Robin are given the chance to use Marshall’s fourth Slap Bet slap on Barney.
Maggie (Joanna Garcia), a girl next door that Ted has wanted to date for years, has suddenly broken up with her latest boyfriend, giving him and other guys a chance to score with her.
Last Cigarette Ever
After quitting cold turkey, Marshall takes up smoking again, with Lily, Ted, Robin and Barney not far behind.
Girls Versus Suits
Ted meets Cindy (Rachel Bilson), a student (PhD candidate) who is close to his own age and who happens to be roommates with his future wife. Barney, meanwhile, tries to pick up a hot bartender (Stacy Keibler) who hates guys in suits by wearing casual clothes leading to a musical number performed by the entire cast.
Marshall finds himself in a quandary as Lily refuses to believe that one of his female colleagues (Amanda Peet) kissed him.
Barney aims to achieve the perfect week: seven days, seven hook-ups, zero rejections, but a sudden accident changes his way of life.
Rabbit or Duck
Ted abdicates responsibility for finding a Valentine’s Day date, and allows Lily and Marshall to "arrange" a date for him; Robin foolishly consents to attend a Valentine’s day party given by her deeply inappropriate co-worker, Don Frank. Barney has a ’magic’ phone but can’t stop answering it.
When a beautiful young woman "hooks" Ted (keeping Ted in reserve as backup while she pursues her own dream boyfriend), the gang discusses their own experiences both as the one who "hooks" and the one on the hook. Guest starring Carrie Underwood as "Tiffany".
Robin is looking to get back at Barney for being insensitive to her after they broke up, hiring self-help author Anita (Jennifer Lopez) to help her out.
It is Lily’s 32nd birthday, that Marshall has carefully planned. Ted has to ruin it all by bringing a stranger to the intimate celebration, an incident that causes Lily to drag out the photo albums and review the endless parade of short-timers in Ted’s romantic life. Robin tries to catch Barney in a bad position to take a photograph.
Zoo or False
Marshall gets mugged which leads Lily to think getting a gun is the answer to keeping them safe. Marshall tries to come up with ways to stop her.
Ted impulsively buys a dilapidated house after his mother’s wedding.
Both Ted and Barney jeopardize Robin’s new relationship by professing their love for her. Meanwhile, after spending a weekend sleeping in twin beds, Marshall and Lily decide to get twin beds at home.
Robots Versus Wrestlers
Crashing a snobby high-society party allows Ted to show off how pretentiously intellectual he can be. Barney, Marshall, and Lily visit a Robots Vs Wrestlers event. Marshall and Lily make a secret pact to start trying to have a baby if they ever finally see Barney’s doppelgänger.
The Wedding Bride
Ted takes a date, Royce (Judy Greer), to see a new hit movie, The Wedding Bride. However, he recognizes its plot as similar to his relationship with Stella, especially since her fiance, Tony, wrote the screenplay.
Lily and Marshall make some hard choices upon seeing Barney’s doppelganger. Robin finally gets an offer for her dream job but someone else would end up with it.