Nettos father Yuuichirou Hikari has made a scientific breakthrough by introducing the synchro chips. If an operator and his or her navi are in a special enviroment known as a dimensional area, they can fuse together in the real world via a technique called cross fusion! Yuuichirous first test subject, Misaki Gorou, attempts the process and sadly fails. Netto offers to try with Rockman, but his father forbids it. Cross Fusion puts enormous strain on the operators health, and battling in the real world could mean death.

(Source: Official Site)