When Posy goes to stay at Pip’s house they have lots of fun together before bedtime. But just as they switch out the light, disaster strikes: Posy realises that she has forgotten her favourite frog toy. Desperate to help his distraught friend, Pip offers Posy a range of different toys to substitute for her frog, including his own favourite frog money box. But none of them will do, ‘that’s the wrong frog!’ Posy wails. It is only when Pip gives Posy his own, very favourite, pig toy that Posy is comforted and that the friends can get a good night’s sleep, at last.