How I Met Your Mother (season 4) (2008)

Stella says "yes" to Ted's proposal. Robin takes a new job as a reporter in Japan, but quickly resigns, returning to New York to attend Ted's wedding, after realizing how much she misses her friends. Stella leaves Ted at the altar to get back together with Tony , her ex-boyfriend and the father of her daughter. Barney struggles with his feelings for Robin and Lily becomes the first person to know about them. He then turns to her for advice on how to overcome these feelings, with little success. His company shifts him to the management team of a new acquisition, Goliath National Bank , where he is joined by Marshall, following a brief period of unemployment.

Marshall and Lily move to their new apartment and debate over whether or not they're ready to have children. Robin becomes roommates with Ted and gets a job as an anchor for a 4 AM news show after Barney sends out her video resume. Ted and Robin decide to sleep together constantly so they won't fight over each other's bad co-living habits. Barney's feelings for Robin begin to become clearer at this point, that attempts to make them stop fighting to prevent this, taking out the garbage, buying many big bottles of milk, giving them stamps, e.t.c, revealing to Ted his love for Robin. For Barney's sake and his own romantic relationship habits, Ted ends his sleeping arrangements with Robin.

Ted finds out Lily has sabotaged all of his relationships with anyone she doesn't approve of and indirectly may have inspired his breakup with Robin (she asked each of them where did they see each other in five years, which is the reason of the breakup in the season 2 episode ). Robin and Ted end up talking about it, causing their friendship to begin moving towards a positive note. Ted finds out that Marshall and Barney have lied to him about keeping the GNB building project alive, despite it being scrapped weeks ago. They try to rectify this by assigning an ETR to design for the 21st floor, but Ted's attempts to be creative with the project cause him to lose his job. However, rather than being angry at this firing, he sees this as a chance to start a new independent career.

While Lily abandons the group and disappears for four weeks after hearing a dirty joke from Barney (this was to cover actress Alyson Hannigan's pregnancy), Ted starts his own architecture firm in his own house, complete with an office and a new male assistant, who Robin ends up sleeping with, Ted fires the assistant, who then smothers Robin to the point of her breaking up with him. However, once Ted re-hires the assistant, the cycle restarts, infuriating Barney, not only upset about the idea of a male assistant, but also with Robin sleeping with him. Since Lily won't talk to him, he decides to slowly reveal his love for Robin to Marshall, who then reveals he already knows. Marshall then lures the assistant to a new job at GNB, leaving Ted to continue his firm alone, but with some support from Robin.

As Barney finally sleeps with his 200th woman, after rubbing it in the face of the childhood bully that taunted him into pursuing it by claiming to have slept with 100 women , he questions what the rest of his life would be about now, leaving him more certain of his feelings for Robin.

Ted, while carrying the yellow umbrella, bumps into Stella and Tony. Tony later decides to visit him, sympathizing with Ted over his loss of Stella. Tony offers him a job as a professor of architecture, which Ted initially turns down.

In the season finale, Robin finds out about Barney's love for her, which she cautiously reciprocates. Although she initially refuses to commit to anything but a sex-only relationship; they seemingly end up together anyway. Ted decides he is done being an architect after his final chance as an independent architect is destroyed by a rival, and finally decides to instead teach architecture classes. The finale ends with Ted beginning to teach his first class, and Future Ted reveals that his future wife is among the students.