After an archaeological dig goes wrong, a group of archaeologists come across a mysterious artifact, which was seen on the first Time King. The following day, a 20 year old woman discovers the same artifact, and becomes a Masked Rider. She soon is joined by various Masked Riders, as she tries to protect the past, the present, and future from an demon emperor. Over time, she is also joined by a rogue assassin, a amnesiac man, and two mysterious men from 20 years into the future.
