An adventure set during the second season of the anime.
From the introduction:
"The battle against Wiseman and the Negamoon family rages on for Sailor Moon and the Sailor Scouts. Unfortunately, when young Rini is gravely injured in one attack, Sailor Moon must reveal her secret identity as Serena Tsukino to save Rini's life. With Sailor Moon's identity exposed, Wiseman travels even further back in time to 1978 to prevent Serena's birth. Wiseman's target: Kenji Tsukino and his pregnant wife, Ikuko. The Sailor Scouts must follow Wiseman to a time before their births to protect the unborn life of the reincarnated Moon Princess... and of her parents."