Now that depends how you define 'main event'.
The Low-End Phantasy Star game might be, seeing as it's taking place concurrently with the High-End game (and the difference is huge--one has a war hero, nuclear dragon, and this... legendary android... thingy; the other has a bunch of characters who haven't done all that much before and basically have a junk ship) and focusing more on cleaning up some mess than any major problems.