This entire discussion is going to be a spoiler so don't read if you intend to watch the series.
Basic premise: bad guys need Prism Stones. There are seven and the last two were sent to Earth to keep them out of the hands of the bad guys when they took over the World of Light. The Prism Stones are in the tails of Mepple and Mipple.
The Annoying Mascots from Hell have to spend most of their time in these transit capsules which look like flip phones, and which have a slot through which various cards are swiped. When Nagisa and Honoka wish to transform, they swipe the "queen" card.
They have to be together to transform, and they have to do it at the same time.
Now, in ep 5, Honoka gets cornered by Pissard, villain #1, who manages to get Mipple from her. And here is the problem.
Does Pissard immediately take the thing back to his boss, who has told Pissard "another failure:=death"?
Nagisa shows up and he gloats over how they can't transform into Pretty Cure...and then he gives Mipple back to Honoka so they can transform.
If I'm a bad guy, here's what I would do: take the one Prism Stone I just got back to my boss. "Here, boss; here's one of the two." This gives the boss a good reason not to kill me. Then I say, "I'll go get the other one now, BRB d00d!" Go back to Earth, grab the other Annoying Mascot even if I have to kill the girl who has it, and take that to my boss. My boss is happy, I'm not dead, and I haven't violated any of my personal morals or ethics because I'm a bad guy and don't have any.
Unfortunately, it also means that Pretty Cure has a bad ending after only five episodes.
Pissard's motivation for giving the thing back to Honoka, right after he's gotten it, is flimsy at best. He has no personal honor and isn't interested in a fair fight. He's already said he intends to kill her for not just giving him the thing.
But the writers had backed themselves into a corner. Honoka and Nagisa are junior-high students; they can't possibly stop Pissard as themselves--only Pretty Cure can do that. Nagisa and Honoka can't transform into Pretty Cure without their bitchy mascot-phones. And they both have to do it at the same time so there's no way Nagisa can turn into Cure Black and kick Pissard around a bit in until he drops Honoka's phone.
And so you end up with a situation in which the bad guy breaks character, completely.
He doesn't really say anything when he tosses Honoka's phone to her. If I'd been writing it, at least I would have had him say something like, "You two have really annoyed me, so you're going to die today. But you'll die too quickly if you stay like that." Toss. "Transform; and then I'll kill you slowly enough to appease my anger."
But he doesn't. He just gives the phone back with some lame comment and waits for them to transform, and then they fight. And at the end of it, Pissard has the gall to be surprised that Pretty Cure, which has beaten him four times already, beats him again.
Naturally there are a bunch of other bad guys waiting in the wings. #2 had his (or her?) flavor text read by the DM in ep 5 and is coming out in 6. And already we can see that he's overconfident. "They're just little girls!" Uh, okay, his pals point out, but you're little, too. "Don't judge me by my size!" O, the irony.
It's the function of bad guys in magical girl series to be disposable, particularly at first. Sailor Moon had about 40,000 villains who were trying to accomplish various tasks for Queen Beryl, each of whom got killed one way or another when they failed too many times. Eventually the Evil Overlord loses his patience with failure and replaces the bad guy.
It's also the nature of bad guys to think, "So-and-so failed because he's stupid and weak. I can easily defeat the good guys!" (Hmm..."Socialism failed in Russia because they didn't do it right! When we do it here, it'll work!") They never think, "So-and-so was defeated. He was a putz--stupid and weak--but I'd better approach the enemy with caution because they're obviously not ordinary humans."
But the bad guys usually are rivals for the Overlord's attention, eager for power, and they typically only get along without killing each other because the Evil Overlord will kill them if they fight. And if Bad Guy 2 learns from the mistakes of Bad Guy 1, it can make it too hard for the good guys to beat them.
The really interesting point of ep 5 is that--once Pissard is defeated--the girls find themselves in possession of another Prism Stone. The bad guys had five of the seven, and the girls had two of them; now they have three--and that is going to make trouble for the bad guys, because now they must obtain three rather than two Prism Stones.
There ought to be a shift in the balance of power, but I've no idea what will actually happen. Because of how it happened we don't know why Pissard had one of the stones on him, unless that was the source of his power; presumably it'll be explained in the next ep or so, which is fine.
One mistake in one episode isn't, and shouldn't, be enough to ruin a series. I'm still enjoying Pretty Cure and I'm hoping that future writing mistakes will be less common, or at least less egregious. The series ran to a lot of episodes and sequels, and I fail to see how it could have done that with the writers making a lot of boneheaded mistakes like this one.