It's bedtime for Little Critter and Little Sister, but when there's a strange sound in the night, the two set out to find the source of the 'tap-tap.' Things that look like monsters in the dark turn out to be innocent in this nighttime adventure! Will they ever find out what's making the sound? Emergent readers will enjoy the humor and mystery in Little Critter: Night Night! Sleep Tight!, a Level One Little Critter I Can Read Comics story.