Siiri, a hardworking millennial, wants to be successful in her job as the advisor to the Minister of Economic Affairs. She craves a promotion. Siiri’s job takes her and the hard-to-handle minister, an unpredictable eccentric boss lady, to a big tango festival in a small Finnish town. Siiri’s father Petri, a former tango artist and an overly optimistic middle-aged man, wants to make himself useful to Siiri while trying to hide the fact that he himself is homeless, bankrupt and finally at his wits end. Over the course of one summer weekend both Siiri’s and Petri’s facade comes tumbling down but the tango keeps going on in the sweet Finnish summer night.

Group of old friends gather in a summer villa to celebrate a surprise birthday party for Mitzi, who is the dramatic focal point of the group. The weekend starts ominously when Mitzi does not respond well to the surprise party. It turns out that Mitzi has just filed for divorce and has been looking forward to a peaceful weekend. The tense situation takes a new turn when Mitzi's best friend brings her new boyfriend for a visit, who happens to be a Swedish film star. Familiar surroundings and the old rituals get to the core of the group and make them forget their adulthood. Revelations, not meant to harm the balance, make them reassess their past as well as their present.

Force of Habit follows the lives of various women throughout one day. Hilla is having a romantic vacation, Emmi is throwing a house party, and Milja is on her way to school when they’re approached by a stranger and things take an unexpected turn. At the same time, Emppu, a young actress, is conflicted as she rehearses for the biggest role of her life. Elsewhere, Aleksi, an inexperienced prosecutor, is preparing for his first court case in haste; Niina, the victim of the crime, has been waiting years to see her case tried. Miia throws a company party, and the mood dramatically changes when her colleague Katja opens up about their boss coming on to her. Miia and a couple of her closest colleagues try to resolve the situation, but how do the others react?