Facing his son's expulsion from school, recent widower, Benjamin Mee decides to begin a new life. To escape the sad reminders of his deceased wife, he buys a large house with a zoo in the backyard. Although reluctant to take on the zoo with all its animals - he decides to give it a try. His daughter, 7-year-old Rosie is happy with the decision, while his 14-year-old son Dylan unhappily retreats into his art work. Benjamin meets the zoo staff and they begin their work to have the zoo up and running by summer. Meanwhile, Dylan and 13-year-old Lily begin a friendship, although Dylan is shy and uneasy initially.
The zoo runs into trouble when Benjamin's bank account runs dry. The morale of the workers starts to dip and they fear Benjamin will sell the property. At the same time, Lily becomes upset with Dylan after he happily receives news his family may be leaving the zoo. However, Benjamin discovers that his late wife has left him an investment account with instruction to use the money wisely while listening to his heart. This discovery lifts the spirits of the zoo's workers. Heartbroken and disappointed about staying at the zoo, Dylan confronts his father and a heated argument ensues. However, they manage to reconcile the next morning. When Dylan admits he misses Lily, Benjamin gives his son advice on reconciling with her.
Prior to the grand opening, the facility passes a very stringent inspection and Dylan, following his father's advice, reconciles with Lily and confesses his love for her.
Although the town experiences the worst rainstorm in a hundred years that threatens to wash out the opening, the weather clears just in time. They are disappointed when no visitors arrive that morning, until they learn that a fallen tree has blocked the access road, leaving many visitors unsure if the zoo is even open. Eventually, the zoo is well received by the community. While searching for more tickets, Kelly admits to Benjamin that she has a crush on him but "can't get a handle on it". She then kisses him and tells him that maybe they can do that again on New Years. After Benjamin tells her that he's looking foward to New Years, she returns to the zoo.
Benjamin takes his children to the place where he met their mother, telling them it was the point in both their lives where they became a "possibility". He takes them through the encounter that day and they begin to imagine their mother there with them.
