The eighth season of the American television comedy series How I Met Your Mother was announced in March 2011 along with confirmation of the ninth season. The season premiered on September 24, 2012 and concluded on May 13, 2013.
Barney attempts to hide the fact that he and Robin used to date, but Quinn finds out when sleep-deprived Marshall and Lily accidentally blurt it out. Meanwhile, Ted forces Victoria to write a left-at-the-altar note to Klaus explaining why she ran out on their wedding.
When Barney designs an extensive pre-nup, the guys take note and propose their own relationship amendments to their significant others. Meanwhile, Quinn is outraged and draws up a pre-nup of her own, which causes friction between the sexes.
When Lily and Marshall have trouble finding a nanny, they learn it’s because of an elaborate scheme Barney came up with to meet girls. Meanwhile, Robin and Ted butt heads over who has a more serious relationship.
When Lily and Marshall can’t decide on godparents for Marvin, they put the gang to the test to see who would make the best one.
As the season of break-ups continues, Ted and Victoria must choose the next step in their long and complicated relationship. Meanwhile, Robin worries about Barney when he chooses a dog to be his wingman.
When Robin is hesitant to break up with Nick, Barney takes matters into his own hands. Meanwhile, Lily and Marshall are desperate for some private time.
Marshall recommends his old law school classmate Brad for a job at his firm, but the interview goes awry, leaving Marshall to do damage control with his boss. Meanwhile, Robin helps negotiate Barney’s return to the strip club circuit.
Marshall takes on his old friend/new nemesis Brad in the biggest case of his career. Meanwhile, the gang reminisces about their own run-ins with the law, leading to a debate over who was the biggest delinquent as a teenager.
Robin is determined to get Barney back no matter what it takes. Meanwhile, Ted fills in as Marvin’s Nanny, leading Marshall and Lily to realize that Ted is using baby Marvin to replace his other baby, the GNB building.
Barney's developing relationship with Patrice leaves Robin questioning his motives. Marshall's widowed mother gets back into the dating pool, but he thinks she may be swimming with a shark.
Robin takes steps to have Patrice fired from WWN, while Marshall puts a jinx on Barney. Later, Ted invites his architecture professor to the dedication of the GNB building, and Marshall and Lily bump into an oddball acquaintance from college.
Christmas approaches and Ted wrestles with whether to tell Robin about Barney's intentions involving Patrice, while Marshall and Lily get an early Yule gift, a night away from Marvin, but a case of separation anxiety strikes and threatens to ruin the evening.
When Robin learns that Barney never asked her father’s permission before proposing, she insists that he seek his approval before announcing their engagement. Meanwhile, Ted keeps his feelings concealed by throwing himself into planning their wedding.
Barney begs Ted to continue seeing his much younger, much wilder girlfriend, even though Ted has nothing in common with her. Meanwhile, Robin must adjust to the power of the bling.
Barney uncovers the lost episode of Robin’s “Underneath the Tunes” as Robin Sparkles. Meanwhile, Marshall and Lily are concerned that Ted’s new girlfriend is a stalker.
Ted is reluctant to break up with his crazy girlfriend Jeanette. Meanwhile, Robin becomes attached to Marvin after finally holding him for the first time.
Ted gets a weird and surprising call from the Captain, which launches the gang into a series of recollections about the last perplexing encounter they had with him.
Barney's legendary relationship playbook, which Robin thought was destroyed, rears its head when Ted and Jeanette break up and Barney decides to use his chick manual to help Ted find a new girlfriend.
Barney reluctantly attempts to sell his apartment by holding an open house, during which Ted and Marshall get mistaken for a couple. Tension arises between Lily and Marshall when her new job causes her to spend less time at home.
Ted and Barney's future versions attempt to persuade present day Ted to go see Robots Versus Wrestlers. Marshall and Robin have a dance-off.
When The Captain asks Lily to move to Rome for a year as his art consultant, she fears that Marshall will resent her. Meanwhile, Ted and Barney become obsessed with a girl who is hiding her amazing body under a puffy coat.
The gang works together to plan a legendary bachelor party for Barney.
Robin desperately tries to locate the item that she buried in Central Park years earlier to wear as her "Something Old" for the wedding. Meanwhile, Marshall and Lily ask Ted to help them pack for Italy, and Barney invites Robin's father to play Laser Tag in order to bond with him.
As the gang prepares to go to Robin and Barney’s wedding, Ted invites Lily to see the house he's finally finished fixing up. Meanwhile, Robin and Barney’s night of relaxation is ruined by an obnoxious couple, and Marshall takes the baby on a last-minute trip to Minnesota to see his family.