In an unknown place, children are trapped in the dark. Their abductor is dead, and you need to find the hiding place and save the children before it is too late. "The Secret of the Mark" is the second part of the Maria trilogy. 50 Clues is an immersive puzzle game that offers the experience of an escape room at home. Combine objects, solve puzzles and decipher codes to complete the story. WARNING: Contains graphic violence. Unsuitable for children.