Tilly and Toby are twins, but very unlike inside. Tilly loves spots - spots on everything - she is 'spotty dotty'. So when Toby gets spots on his tummy and has lots of extra attention because of his chickenpox, Tilly wants it too. Dad explains that she could catch it from Toby, so Tilly follows him around until she does indeed get spots - everywhere, even in her nose! Ever so pleased, she soon finds that the spots itch and she doesn't feel well. Besides, Toby can now go out to play, and she can't. A special bath helps, and when Tilly is better, mum bakes a special end-of-chickepox cake with all sorts of spotty things in and on it. Tilly decides spots are 'out' and she's now into stripes. Gentle pictures show us a happy family (with a hands-on dad) sharing the ups and downs of a childhood illness.