Rightstuf describes it:
A clandestine organization known as the MBI has issued an edict that threatens to end the lives of Minato and his luscious companions once and for all! The cutthroat organization’s Sekirei Plan will force all busty brawlers and their masters to engage in a flesh-baring fight to the finish. Only one amazing pair will be left standing when this curvaceous cavalcade of carnage has come to a conclusion. Does Minato have what it takes to survive the bombastic barrage of breast-jiggling blows coming his way?
(May contain spoilers if you have not seen the first season. I will keep the spoilers a minimum.)