Burger King is offering young Thor fans a bonus serving of comic book content. The restaurant chain is kicking off its sponsorship of the Marvel film, which hits US theaters on May 6, by offering kids exclusive access to new chapters of the Thor comic on ClubBK.com.

Visitors will have the opportunity to unlock one of four never-before-seen digital comic chapters using the code that comes with the purchase of a BK Kids Meal. The bonus series serves as a prequel to the film and tells the four-part adventure of a young Thor and his childhood friends.

The promotion extends across eight BK Kids Meal premiums – four that target girls and four for boys. The meals include figurines and accessories inspired by the Warrior Maiden Sif, such as the Asgardian bracelet and headband.

The promotion will be supported by in-restaurant merchandising and national television advertising that features footage from the upcoming film.