Molly gets sucked into an ancient portal device, and returned as an 18 year old who's reverted to a savage mindset. Elsewhere, Worf takes a crack at babysitting Yoshi.
- Adult Fear: The O'Briens must not only deal with the grief of losing Molly when she falls through the portal, but the challenges of having a child they can no longer relate to once they manage to get her back. And that's before being faced with the reality their child is unable to function in civilization, and deciding that her only hope for a full life is to send her back to the past despite knowing they'll never see her again.
- Baby Talk: Worf is teaching Yoshi a Klingon hand-eye exercise by shaking a rattle and going "Gung, gung, gung."
- Bar Brawl: Molly attacks Quark and his patrons, smashing furniture and bottles, until she is stunned by security.
- Bittersweet Ending: The O'Briens getting their daughter back at the end is certainly happy, but it's tempered by the fact her adult self ceases to exist because of the resulting paradox. The scene at the end where Young!Molly draws the exact same picture as Adult!Molly is particularly heart-wrenching.
- Butt-Monkey: And not just Miles this time. The whole O'Brien clan gets to suffer.
- Do Wrong, Right: After Odo catches O'Brien and company at the airlock, he tells the chief he's disappointed... because Odo thought if anyone could break someone out of a holding cell and sneak them off the station undetected, it would be O'Brien. He then opens the airlock and lets them go.
- Forgotten Phlebotinum: If the main characters had remembered they have access to a reliable time machine they've used twice already, or the "Slingshot-around-the-sun" trick used by the TOS crew several times, the whole plot of this episode could've been avoided. Justified in they still need to know precisely when Molly was transported to for them to get her back.
- Grandfather Paradox: The adult Molly who finds little Molly never exists if little Molly did not stay in the past. Sure enough, once little Molly goes back through the portal, adult Molly disappears.
- Grievous Bottley Harm: Molly stabs an alien in the stomach with a broken bottle.
- My Future Self and Me: Little Molly thinks the woman who found her, the grown up version of Molly, is "so nice".
- Nubile Savage: What Molly is returned as.
- Picnic Episode: Molly was so excited to go on a picnic.
- Portal to the Past: The portal left behind in the cave.
- Ret Gone: Adult Molly saving young Molly causes this.
- Set Right What Once Went Wrong: 18 year old Molly sends little Molly back through the time portal.
- Wild Child: Molly lives alone for 10 years and returns without social skills or language.
- Year Inside, Hour Outside: Molly ages 10 years in the one day it takes to repair the time portal.