From the preview, "In Mugen Souls, Lady Chou-Chou and her peons took over their solar system, proving she’s the best goddess ever. However, she’s ambitious and thinks only one solar system is not enough. She orders her peons to head to a new and larger solar system to expand her power and influence. However, this system isn’t unoccupied, which means she’d have to beat any other heroes or gods in her way.
Except Lady Chou-Chou runs into something unexpected – Mugen Soul Z‘s star. A new hero named Nao wakes up a girl in a coffin named Syrma, the protagonist this time around. Though she has a bit of amnesia, she does remember she’s some kind of goddess, just like Chou-Chou. Naturally, the two of them run into Chou-Chou and her head peon, Ryuto. A fight ensues, the overpowering Chou-Chou and Ryuto win, Chou-Chou gets grabby, falls into Syrma’s coffin, and has her powers sapped..."