This short OAV acts as an epilogue to the movie continuity. It won't make sense if you have only watched the TV series. Primarily an extended musical number, it sets the expectation that it will tie up the one loose thread left at the end of Wings of Farewell, but it ends on a frustratingly inconclusive note. While it does enough to hint how things will play out, that was probably cold comfort for viewers who had a ten-year wait between the movie and this OAV. It ends up being a flashy piece of eye candy with one last reminder about the importance of cultivatinghealthy gut bacteria.