Marion has just moved to the German side of the French-German border to follow her boyfriend - Lukas - who recently got a job in a theater company. On the day of her 28th birthday, Lukas surprises Marion by proposing to her. Aged now 29 and 28, they have been together for three years and are the happy owners of a brand new house - all the ingredients are gathered to become adults and commit - or so they thought.