One Piece, while still full of zany characters and wacky antics, is not the light-hearted series it once was. While there were hints of it throughout the preceding story arcs, the fact that Luffy is now actively breaking into a dangerous prison to rescue his brother from death row really hammers home the idea that there's more at stake here than just becoming the King of the Pirates. Granted, the pasts of Nami and Robin specifically also got very dark, but neither of them were truly in danger of losing their lives. Ace, on the other hand, most definitely is.

With his crew spread out thanks to Bartholomew Kuma, Luffy is on his own as far as breaking into the notorious Impel Down jail goes. Fortunately he has managed (all unawares) to charm the Pirate Empress Boa Hancock into sneaking him in, and with her status as one of the Seven Warlords, along with her devil fruit power, this turns out to be the easiest part of the rescue process. Once he's in, however, Luffy must descend the levels of Impel Down to where Ace is being kept, something that ought to be significantly more difficult. Given that this is Luffy, that difficulty turns out to be rather over-rated. In part this is because he's ridiculously strong, but it's also due to the fact that he's incapable of seeing people as anything but friends unless they're actively hurting him or his crew. That's both a large part of his charm as a character and in this segment of the show, as it enables him not only to work with Buggy the Clown and Mr. 3, but also showcases their confusion and entertaining resentment of somehow ending up on the same team with the guy who made them look like fools and helped to land them in Impel Down in the first place. This is funniest with Buggy, who honestly can't seem to get away from Luffy even when he actively deserts him and doesn't quite know what to think of the former Baroque Works members who end up joining them on their journey. (To be fair, I doubt many people know what to think of Bon Clay upon first meeting him…)

Whether or not Buggy, Mr. 3, and Bon Clay are your personal favorites, there's really something great about them all running around a deadly and hellish prison like a bunch of lunatics. The word “hellish” really does fit, because the whole place looks like a combination of Dante's Inferno and traditional Japanese Hell Scrolls. Eiichiro Oda's trademark monsters are naturally present for the guys to defeat, but beyond this, it is very clear that Impel Down is a remarkably inhumane prison. While the overall tone is more “Buggy and Luffy's Wacky Prison Adventure” than anything tenser, we're never really allowed to forget that Ace's life is on the line. In part this established through glimpses of the other prisoners, but also by flashing over to Ace in his cell and Boa Hancock's enacting the cover story that allowed her to smuggle Luffy in – a visit to the condemned. From this we can see that Ace has essentially given up, which is in stark contrast to the way the story generally presents its characters. Even when characters have previously thought about giving up it has been turned around, such as Nami asking for help or, in a sillier sense, Zoro striking a pose when being turned into a candle. Now it is always possible that this can be changed, but there's a bleak despair in Ace's situation that feels markedly different.

Mixed in with these prison break episodes are four that serve as a tie-in to the Strong World movie, loosely linked to this story arc by the fact that the villain of that film, Shiki the Lion, was the only man to escape from Impel Down. While this is a definite interruption on the progression of the plot, it's also a fun return to the original flavor of the series, to say nothing of a chance to see the rest of the crew. The bad guys are unfortunate Mexican stereotypes (which may be driven home for some viewers by the accents in the English dub), but overall it feels like a nice break…and if you don't want the interruption, there's no reason why you can't skip them and watch them later.

The English dub sounds oddly stilted in a couple of episodes, but if you pay attention, that appears to be due to the lip flaps and the differences between English and Japanese as spoken languages. New characters such as Sadie and the wardens of Impel Down are fun to listen to in both languages, and it's worth mentioning that these episodes also introduce us to Jinbei, a fishman worth paying attention to. This particular set returns the dub commentaries to a more traditional form rather than the interviews or storytelling types that have appeared on other sets, and both are interesting in different ways – episode 432, with the actresses for Sadie and Domino, discuss how they began dubbing anime while episode 425, with the voices of Hannybal and Magellen, should probably be rated PG-13 and gives the impression that maybe one too many frappuccinos were involved. The other extra beyond the usual trailers and clean opening and closing is “Chopper Plays Doctor,” where Brina Palencia, voice of Chopper, attempts to use her medical knowledge to play the board game “Operation.” It goes as well as you might expect.

While this isn't the best set of episodes, it is getting the story ready for its next big moment, and it doesn't do too shabby a job of it. The interrupting Strong World episodes do feel oddly placed in the release (although doubtless that was much less the case when they originally aired), but they are easily skipped over if you don't want to be pulled out of the Impel Down storyline. With enough to keep you interested in terms of both plot and goofy antics, this is above average without being spectacular as it builds towards something that will have larger repercussions on the story's world.