I suggest the logline, and perhaps the concept, may need to be rethought. As as presented, the story seems to be 1] backward-looking (only) 2] with no apparent antagonist, and 3] no well-defined stakes.

As a general rule, plots are forward looking, not backward looking. In stories where characters are looking backward in time they are doing so in order to solve an urgent problem in the present or near future.

Stakes: What difference will it make in her present and future life if she does piece together the puzzle? Conversely, what does she stand to lose in the present and future if she fails? Why should the audience worry what the consequences will be if she fails?

What’s the urgency? Other than curiosity why MUST she know about him NOW?

Thanks for the clarification. The premise raise all kinds of interesting complications and plot twists that you can’t cram into a logline, of course. But If you can slip in a few words that it’s a temporary swap out without inordinately lengthening the logline, I think it might be a winner.

On suggestion (beyond the scope of the logline) is that as a result of the swap out the antagonist gains a few high cards in his hand (mind actually), to play, too. Better yet, he comes out ahead as a result of the swap in terms of memories,cognitive ability, whatever.

Or at least that mental instability is a side-effect in the brain of the good guy, too, as a character flaw. (An unavoidable hazard for all consciousness’s involved in the swap.)

I suggest that because one of the standard m.o.’s for escalating suspense and jeopardy is for the bad guy to get all the luck, all the breaks. The good guys get none; he has to work for everything.

fwiw