After his recent feats, Touma is recognized by the others as a full-fledged member of the Sword of Logos, but when the Megids prepare multiple Alter Books for their next plan, Tetsuo Daishinji, the order's mechanic, joins the fray as Kamen Rider Slash after repairing his own weapon.

Touma and the others are shocked to discover that Calibur is Daichi Kamijo, the previous Kamen Rider Saber while Kento is in distress over not knowing his father's whereabouts. Meanwhile, the Megids strike again and Daichi appears with a new power that makes him a bigger threat