Jeff Brown likes being an ordinary boy. Then he meets the new girl, Tilly Perkins. Tilly is different, but she's also brave and generous, tells amazing stories and has a great imagination. Jeff thinks Tilly is a lot of fun, but the rest of the grade-three class thinks her games and stories are not much more than outright lies. Then Jeff has a birthday party and the whole class is invited. Tilly promises Jeff two white mice as his present, but arrives at his party empty-handed. The other kids think she has broken her promise. As the party draws to an end, Jeff has to make up his mind. Even if Tilly is just pretending, which would he rather do? Play exciting games with Tilly's imaginary mice, or just go back to the ordinary games with his other classmates? A warm story that will have readers sympathizing with Jeff and his struggle with peer pressure.