Mikami Inaba was fighting a person from another school on her school's rooftop. As they fought, her friend Haru appeared. Seeing Mikami distracted, the man charged at her, causing both of them to break the nearby rabbit cages & fall off the roof. As Mikami fell, she desperately grabbed the rabbit. Suddenly, a flash or pink light appeared. Mikami fused with the rabbit, and gained another personality, called Mimika. Now, Mikami only appears when various people threaten her and her friends. Otherwise, she takes on the form of Mimika. (Source: ANN)

Valkyries—legendary female warriors from the land of gods, Asgard—are sent by Odin to protect Earth against the growing threat of demons. To overcome these threats, nine valkyries under the guise of the Saotome sisters will have to level up by performing a variety of romantic acts with their official lover, Einherjar. Meanwhile, the socially anxious Takuma Akutsu learns that Odin has chosen him as the valkyries' lover. Despite his utter horror, however, he agrees to let the sisters stay in his big yet empty house to help them in their war against demons. With nine beautiful women sharing his roof, will Takuma manage to prevail over his fear of society and become someone worthy of saving the world?

Vandread The First Stage (season one) was immediately followed up by this OVA. This OVA, also known as Vandread Taidouhen Stage (The Movement Stage) was a recap of the first 13 episodes with additional footage. So, Vandread Taidouhen is not really a bridge between Vandread The First Stage and Vandread The Second Stage (season two). It was made to bring new viewers up to date as to what happened during the first season (Source: AniDB)

Vandread Gekitouhen (Vandread Turbulence), similiar to Vandread Taidouhen, is an OVA summary of Vandread the Second Stage plus several extra scenes (Source: AniDB)