In a drab tenement building beneath a moody, marbleized sky that changes color as the pages turn, everyone goes to sleep except Roberto -- and as each child begins to dream, a different swirly, smoky light fills his window. Roberto, who can't sleep, sees through his dark window that Archie's cat is cornered by a big dog. "Then it happened!" Roberto's pajama sleeve brushes from the window sill the paper mouse he'd made in school that day and as the mouse sails down, its shadow grows and grows until the dog howls and runs away. "Wow! Wait till I tell Archie what happened! That was some mouse!" Understandably then in the morning when the other children are seen brushing hair, greeting pets, etc., one window is a pink and yellow glow -- "Roberto was fas asleep dreaming." There's little change of scene but the subdued colors of windows and sky make for ali the variety, and the paper mouse's growing shadow all the drama, that's required. And though it's almost all seen from outside the building, Keats -- who shifts momentarily to Roberto's view of the dog and cat -- makes it easy to share the boy's perspective and the muted sense of reverie.