She was having a perfectly bad day... Then he came along and spoiled it.

Melanie Parker, an architect and mother of Sammy, and Jack Taylor, a newspaper columnist and father of Maggie, are both divorced. They meet one morning when overwhelmed Jack is left unexpectedly with Maggie and forgets that Melanie was to take her to school. As a result, both children miss their school field trip and are stuck with the parents. The two adults project their negative stereotypes of ex-spouses on each other, but end up needing to rely on each other to watch the children as each must save his job. Humor is added by Sammy's propensity for lodging objects in his nose and Maggie's tendency to wander.