Mark and Alyssa are twins. When their Grandma dies under mysterious circumstances, she leaves Alyssa a necklace that she soon finds gives her the ability to go back in time and observe. Mark also has a ring left from their Grandpa, who died years ago. The ring gives Mark the ability to communicate with ghosts. The two find a bunker hidden beneath the school. Upon going to explore it they find someone who explains that a danger is coming, and it is in their hands to stop it.