Ahead of the Christmas Day release of Robert Eggers’ buzzy new horror film Werwulf, Focus Features has launched an alternate reality game in which fans must solve a puzzle every full moon from September through November to win a prize.

Located on DevourethAllMankynde.com, the Werwulf alternate reality game challenges fans every full moon for three months to seek out a hidden “sign” on various digital platforms. There is only a 24-hour window each full moon to find the “sign” and record your answer on the site.

To find the signs, the website will offer a hint for each full moon. The first hint reads: “X marketh the place wher thou sekest.”

Eggers’ fifth film reunites him with his Nosferatu stars Aaron Taylor-Johnson, Lily-Rose Depp, and Willem Dafoe. It follows a farmer (Taylor-Johnson) who moves with his wife (Depp) and children to a remote medieval village. Dafoe stars as a local hunter targeting the savage wolf that has been ravaging the town. Focus Features released the film’s official second trailer today.

The game and prize are only available to US residents.

Werwulf hits US theatres on Christmas Day and UK theatres on New Year’s Day.