Time Loop One-Shot

I signed up to DM a one-shot around Halloween. Its my first time and I’ve been preparing a story about the players being part of this organization that handles distortions in the timeline.
The Prologue is actually the climactic ending that shows the helpless defeat of the party. It essentially makes the players encounter and defeat alternate versions of themselves (unknowingly) then BECOME the versions of themselves they just defeated and forced to fight themselves (making them relive the same fight but from the losing side).
The ending is essentially the Prologue played out exactly as before, showing the players that not only did they not “win” but they are stuck in the timeloop seemingly forever.
There is more to it but i feel like ill have to “railroad” the players in order to make this work. Is this a good idea?