On the coattails of Journey (2013), Becker gleefully expands and details his award-winning fantasyland, growing even more ambitious with his storytelling. When readers last saw the boy and girl protagonists, they were sharing a tandem bike; this adventure opens with the children sheltering from raindrops under a bridge, the bike propped up against the wall. Suddenly, a desperate king bursts through a door set into the base of the bridge. He charges the two young heroes with collecting the six magic crayons that will defeat his realm's enemy once and for all. Supplied with a map indicating where the crayons are hidden, the kids find each one (the girl stores them in a crayon bandolier), leading to a showdown with the bad guy that ends with a brilliant, rainbow-hued win for the forces of good. Harold-like, the children use the crayons to draw themselves out of scrapes along the way. Broadening his palette, Becker fills his book with myriad colorful details that will reward sharp-eyed fans. At the same time, his ink and watercolors evoke different kinds of architectural wonders (everything from Atlantis to Chichén Itzá). Part Indiana Jones, part Avatar: The Last Airbender, this book proves to be more exciting than its Caldecott Honor predecessor, emphasizing adventure over evocative metaphor. Breathtaking in scope, consider this a wordless testament to the power of not just imagination, but art itself; picture books rarely feel this epic. (Picture book. 4-8)