8-year-old Lisa grew up in an orphanage. She had a happy childhood there but she is very excited when she hears that she will be adopted. Eva, her 'new mother', is a journalist, and Martin, her 'new father', writes advertising copy. Lisa can hardly wait to see her new home since she only knows about 'families' from books and television. What Lisa does not know is that Eva and Martin are planning to split up and are waiting until the adoption goes through before they file for divorce. At first, their new daughter is busy with her life, her new school, her new friend, the new apartment and her love for the Museum of Natural History, where her best friend - the Sabre-toothed Tiger -lives!
However, she is soon irritated by the fact that Martin leaves home before she wakes up in the morning and hardly to be seen in the evenings too. Since Eva is tight-lipped about the situation, Lisa does not dare to ask. But when she sees Martin coming out of an advertising studio arm in arm with a model, she realizes that families aren't quite like what she had imagined.