Mother of three young children, Marlo (Charlize Theron) lives in a constant state of fatigue. With a newborn child and the autistic son's difficulties in school, life becomes increasingly difficult to handle, so when her brother offers to pay for a night nanny, she reluctantly agrees to test it out. The young and energetic nanny Tully (Mackenzie Davis) appears in her family's home at night, and soon her energy begins to infect Marlo. Both women form a strong bond that supports and challenges Marlo. Tully is the third collaboration between director Jason Reitman and scriptwriter Diablo Cody, their first film, June, won the Oscar for best script in 2007.