Doki Doki Pretty Cure is, despite being the eigth continuity and tenth season overall, the first series of the Pretty Cure franchise to have a pure Myth Arc without any pure filler episodes.
All information are not marked as spoilers!
Episode 1-6: The first four episodes feature the appearance of the four Precures. The fifth episode focuses on the identity of Cure Sword which is revealed in the sixth episode.
The seventh episode tells the backstory; the Doki Doki Precure are complete.
Episode 8-9: The eighth episode features Ai-chan's birth and the ninth episode features her upgrade-powers.
The tenth episode has Makoto going to Mana's school which establishes her as a full teammate and losing her status as an Aloof Ally completely.
The twelfth episode features Regina in the end who is is revealed to be King Jikochuu's daughter in the next episode.
Episode 13-15: The thirteenth episode features the yellow Royal Crystal. The blue and purple Royal Crystal appear in the fourteenth and fifteenth episode. The new group finisher move is also featured in the fifteenth episode.
Episode 17-19: The seventeenth episode features the red Royal Crystal that is stolen by Regina, which makes her act more evil, and the reveal of Joe Okada's real identity. The eighteenth episode features the last Royal Crystal and Jonathan's romantic relationship with Princess Marie-Ange. The nineteenth episode brings the crystals together at the end of the episode, setting up the plot for...
The twentieth episode, revealing the location and subsequent abduction of the Princess and Regina's Heel-Face Turn.
Episode 21-23: The 21st episode has them saving the princess from the villains and Regina fully completing her Heel-Face Turn and joining the Precures. But in the 22nd episode, Regina undergoes Face-Heel Turn, thanks to her father King Jikochuu, and defeats the Precures. But in the end of the episode, Cure Ace appears and saves them. The following episode introduces Cure Ace and her civilian identity and two new Selfish villains.
Episodes 23-26: Cure Ace acts as a mentor to the other Precures, resulting the power-ups of Cure Heart, Cure Sword, Cure Rosetta and Cure Diamond in each episode, respectively.
The last two episodes have hints that Mamo and Ira will make a future Heel-Face Turn, especially the latter.
Episode 27-28: The 27th Episode gives some background information about Aguri aka Cure Ace, including her 5 minute time limit. It also marks Cure Ace officially becoming part of the team, as from this point on, the opening and ending now feature her as well. The following episode gives us Cure Ace's Power-Up.
Episode 29-31: The 29th Episode shows the development of the partnerships between the Precures and their fairies who all transform into humans. That gives Aguri the occassion to talk about the final test of the Precures. In the 30th episode, they have a Hopeless Boss Fight test against the fairy Melan, but they gain the Legendary Mirror. They also learn about the three legendary Precures, one of whom was Melan's partner Cure Empress. And in 31st episode, they gain their own Magical Lovely Pads and their new finishing move Lovely Straight Flush. Leva and Gula are also killed by Bel in the end of the episode, which essentially made them Arc Villains from episodes 23-31.
Episode 32-35: The Selfish Trio gets an upgrade by Leva and Gula's absorbed energy. Cure Ace, Cure Rosetta Cure Diamond, and Cure Sword get their new attacks Ace Mirror Flash, Rosetta Balloon, Diamond Swirkle, and Sword Hurricane respectively. There is also a focus of Ai-chan's growth and her cry is able to enhance the power of the villains and Monsters of the Week.
The 36th episode subtly foreshadows Bel's evil plan with Ai-chan. Also, it's like a Sequel Episode to 29.
Regina awakes in the end of the 37th episode.
The 38th episode executes Bel's plan with Ai-chan and destroys Ira and Marmo's Blood Rings.
The 39th episode has Regina gaining possession of the Miracle Dragon Glaive, a weapon used by one of the three legendary Precures. Cure Heart uses her new attack Heart Dynamite. Also, it is shown how strong the Cures have become since Episode 23.
Episodes 40-43: Focuses on the Precures and their respective relationships with Regina, slowly turning her back to the side of good in each episode. The Cures unlock another Mid-Season Upgrade in episode 40, including the new group Finishing Move Royal Lovely Straight Flush.
Episode 42 and 43 foreshadow Aguri's mysterious origins and her possible relationship with the Trump Kingdom.
Episode 44: Sir Joe is back, and this time it's the real him.
Episode 45-46: In the 45th episode, Joe reveals he has found the Eternal Golden Crown. Aguri and Regina are also revealed to be the light and dark sides of Princess Marie-Ange, respectively. Episode 46 also builds upon this fact, revealing that the Selfish King was once the king of the Trump Kingdom before being Brainwashed and Crazy, Aguri and Regina are the light and dark sides of Marie-Ange's psyche, respectively, and the remaining body of the princess turned into an egg that would soon become Ai-chan. The stage is also set for the final battle of the show.
Episode 47: The final battle of the show ensues. Regina makes yet another Heel-Face Turn and joins the Cures.
Episode 48: The final battle continues and the Trump Kingdom King is freed from the influence of the Jikochuu.