The title refers to the period when the animals of the daytime are retiring and those who populate the world at night are becoming active, "Come and watch them switch places."
The magnificant illustrations have lots of detail and come alive with bold bright colors. Each animal has a two-page spread under an arch. Above the arch across both pages are pictures related to both the daytime and nocturnal animals being featured. For example, the goshawk hunts during the day (one spread) and the owl flies at night (a second spread) but they both are looking for mice (pictured over the arch in both picture spreads).
The home of the opposite daytime or nighttime animal being featured can be seen in the illustration for the other. The swallow and the bat both hunt mosquitoes. The butterfly and the moth each take nector from the flowers. The snowy egret and the night heron look for frogs.