Cody wrote both of the films, as well as the 2011 film Young Adult, which starred Charlize Theron . In Tully, Theron reunites with Cody to play Marlo, a mother of three whose life changes when she meets Tully (Mackenzie Davis), a night nanny hired by her brother to help out with the kids. The two form a "unique bond," and while the trailer does nothing to help us figure out what that means, it does paint a painfully relatable picture for all new moms.