When Pete (Mark Wahlberg) and Ellie (Rose Byrne) decide to start a family, they stumble into the world of foster care adoption. They hope to take in one small child but when they meet three siblings, including a rebellious 15 year old girl (Isabela Moner), they find themselves speeding from zero to three kids overnight. Now, Pete and Ellie must hilariously try to learn the ropes of instant parenthood in the hopes of becoming a family.