A string of murders have been identified by Saito as the product of Hiten Mitsurugi Ryu. There are two suspects: Himura Kenshin and his master Hiko Seijuro the Thirteenth. Unbeknownst to them, a third user of their exalted style has time travelled to the future: Hiko Seijuro the Twelfth. Shenanigans ensue.