IIRC, in Back to the Future the MC traveled back in time somewhat by accident while trying to run for his life. It wasn't something like 'I have to go back otherwise my mom and dad will never get together', which is an analogy for what happens when Darci tells us we have to return to save her mom. Her mom is already safe and sound in her home, so it doesn't truly work as a plot device.
But this can still be written in a way that will make sense. Maybe the mysterious guy who probably sent the message to Darci had other reasons to send us back in time. And he knew we'd act on impulse trying to help Darci and her mom, and wouldn't think logically. That's pretty plausible, and I trust the dev to come up with e good explanation in the upcoming episode.
Regardless, I'm excited thinking we might get some quality time with Luna