Whale Trail is an iOS and Android game about a flying whale whose eyes take up one-third of her body. She must travel the skies in search of a good optometrist, and is heartbroken to discover that specialists generally don’t open up practices in the sky. In all seriousness, Whale Trail‘s relaxed gameplay and sunny, rainbow-colored environments have made it a hit on the App Store, and like Angry Birds and Fruit Ninja before it, Whale Trail is looking to expand its brand beyond the mobile market. Its choice of medium shouldn’t come as a surprise: children’s books.

Ustwo, the London-based developers of Whale Trail, has signed into a publishing deal with Penguin Books. Penguin plans to release digital and dead tree books based on Willow’s struggles against the Thunder Bros. Prepare for action, murder, intrigue, and an R-rated movie deal!–Or maybe just some fun kids’ books that are happy and colorful.

The first Whale Trail book will be released in a digital format in October 2012. Beyond that, more digital books will arrive in 2013, along with the paper-and-ink publications.

Ustwo didn’t reveal how much it made from its publication deal, but it plans to spend the money, plus the profits it’s made from the game so far, into expanding the Whale Trail IP, and building on the current release. Ustwo says that it’s spending about £50,000 ($79,000) on the next game update.