Told from separate viewpoints, Chess, Emma, and Finn Greystone, ages twelve, ten, and eight, investigate why their mother went missing and uncover their ties to an alternate world.

"Colin and Nevaeh are great at finding things. After all, they found each other and became best friends--even though their parents are business rivals. They also found hidden boxes of secret letters, which led them to unravel mysteries about kids from the 1970s. But when they started Mystery Solvers Inc., they didn't expect to be asked to find a ghost. Ree recruits them to investigate a series of old, spooky photos left behind in her family's new...