Three decades have passed since a boy named Keita wielded the legendary Youkai Watch, and the world has forgotten the bridge between humans and supernatural creatures. The watch itself vanished into the void, deemed too dangerous to let exist. But when a sinister plague emerges, everything changes. A mystical virus called Onimaro targets those harboring dark intentions, warping them into twisted demon-like beings called Kaodeka Oni. The infection spreads unchecked, and chaos breaks out across the city as a comet draws near. Only those chosen by a new Youkai Watch can stand against the threat, and with it comes the chance to restore the bond between humans and youkai. The result is a supernatural film about saving both worlds from destruction.