Plot hole: In Russia, Soldier Boy is shown heading to the airport, He wanted to get to the US and start his revenge against his team. Problem is: he has no documentation and money to take a flight. Even if he stole the money somewhere, still would be impossible to travel without the proper documents.
The Tale of the Mystical Mirror - S5-E3
Plot hole: It makes no sense that Ms. Valenti gives all of her employees a compact mirror and also invites them to her home. Any of them could open their mirror while standing near a painting of Ms. Valenti and they would discover the secret, as Cindy does.
Suggested correction: The compact mirror includes a palette of cosmetics. Cindy shows it to Laurel, who says, "She gave one to me, too, like we're ever gonna use it." Presumably, the employees are mostly using the free samples of cosmetics from the shop displays. I myself have owned some compacts that I didn't always want in my purse (if they were too big or awkward in a certain purse).
The Feminum Mystique: Part 1 - S1-E5
Plot hole: If her younger sister Drusilla is sent from Paradise Island to retrieve Diana, how did she get to Washington DC or wherever, she had no way of knowing where her older sister would be.
Plot hole: Dillon was quickly identified by the city sensors as having metal parts, thus classifying him as a threat to the city. Yet Tenaya, who is essentially a cyborg, tries out for the Green Ranger without setting off the same sensors.
Suggested correction: Tenaya wasn't caught because the guards assumed the equipment was faulty. It was giving positives all day because of all the sleeper agents we find out about later.
Plot hole: Skye's mother, Deborah, was held hostage by the Sixers for several years, though everyone believed she had died in an epidemic and was buried in Memorial Field. The Sixers kept her alive with medicine only they had to force Skye to act as their spy. Even though Terra Nova has a medical clinic staffed by doctors and nurses, it was never noticed that no one had witnessed Deborah dying, her body was never placed in the morgue, that was there no record of her being buried, or even questioned that there was no corpse. Deborah just disappeared without a trace and nobody wondered about it.
Plot hole: The nuclear explosion is on Liberty Island, a small yield, but nonetheless big enough to move an enormous amount of water towards the coasts on all sides. When we see Sertrakian and the others at the harbor no water is heading their way - they should be washed away by it. (00:37:30 - 00:38:45)
The Beacon - S1-E26
Plot hole: Barrows introduces himself as "Dr. Dennis Barrows," and Teddy asks, "What's a doctor?" As the isolated villagers have never heard of doctors, Teddy would have no way to know that "Doctor" was a title/profession and not simply part of Barrows' name. He should have asked, "What kind of a name is Doctor?"
Plot hole: Jaden activates Miracle Fusion, allowing him to fuse the Elemental Heroes Flame Wingman and Sparkman in his graveyard to summon Shining Flare Wingman. However, Flame Wingman was never sent to Jaden's graveyard. He activated De-Fusion (allowing him to summon Avian and Burstinatrix) when it was about to be destroyed, which meant Flame Wingman was sent back to his deck and not his graveyard. (00:17:13)
Plot hole: The episode's climax concerns Bernie rushing to the airlock to stop the rest of the crew, who are infected, from flushing themselves into space. Except that he's infected too, so they can't flush without him anyway.
Plot hole: During "the changes" people fear machinery, but the woman who pulls back her curtains to watch Nicky and the sikhs go past is wearing a watch.
The White Mountains: November, 2089 AD - S1-E13
Plot hole: The main characters are being pursued by Tripods, mind controlling alien machines. My question is, if the Tripods can turn humans into 1600's puppets, complete with foxhunts, why don't they make some of said mind-controlled humans help with the pursuit?
Plot hole: Why would Danger Mouse go on the roller coaster at the end without seeing Greenback go on it first? Greenback went first in the ghost train. It also doesn't make sense that Danger Mouse would go on it when Penfold pretty much tells him flat out that it IS a trap.
Plot hole: Sydney is able to surmise from the artwork (we could also say from the writing, but her rival is one step ahead of her for 2/3 of the episode and it is established that he does not know the language) the precise location of the koi in Lumbini. The map is 150 years old, but there's no way even with a big stretch of imagination to buy that they both'd be able to pinpoint with such ease and certainty its location in the basement of a random building in the bustling market center of a town, that surely changed plenty during the past century and that does not bear any special landmark.
Plot hole: The Jupiter 2 crew is duplicated; however, the aliens had never seen Penny (or Judy I think). How can they be duplicated? The aliens don't have ability to know who were there, or they wouldn't have questioned Smith about the crew. Also, they do not know Smith and Will are hiding. So, they don't arm to have any special power to know beyond what they actually observe.
Plot hole: The way slipstream works is wildly inconsistent across the show. Sometimes, they have to travel a significant distance to find the nearest slip point, and other times, when it's required by the plot, there's a slip point conveniently right next to the ship.
Suggested correction: How is this a mistake? Unless the points are evenly distributed and all close to each other, they are going to be different distances away.
Plot hole: In the pilot, it is established that the surface of anything/anyone made invisible by "quicksilver" is freezing. (Darien gets caught in the women's shower because the mist freezes on him. He freezes the beer mugs for the doctors.) But in later episodes, nobody notices him standing invisible - and freezing!? - next to them.
Plot hole: Tori somehow knows who Marah and Kapri are, despite never meeting them before.