Pretty Cure GoGo Heart is a fanon story based on Pretty Cure Max Heart and Yes! Pretty Cure 5 GoGo. It focuses on what happens after the two series end, and on twins named Aruna and Von, who lived in the Garden of Light until now.
When Aruna meets Pretty Cure 5 at Natts House, Nicole promises to help her to find her twin.
The main characters are Aruna and Von, although the Pretty Cures have major roles too.
Aruna's twin brother Von is a little boy who has been kidnapped by a Zakenna. He holds the powers of Light. He is the more calm one of the two, but is still pulled along in Aruna's antics. Upon being reunited with Porun, Von's powers gain an enormous boost, allowing him to transform into Cure Gold.
Their mascots, Coco, Natts, Milk and Syrup, all have human forms, although Milk is the only one who can remain in human form without getting tired out. She uses the alias Kimberly and can transform into the warrior Milky Rose. Coco and Natts are the kings of the Palmier Kingdom, and Syrup is a delivery boy who can transform into an aeroplane-resembling form.
Mepple, Mipple, Porun and Lulun are the group's mascots, and also are the twins' close friends. Mepple is the Chosen Hero, and his only love Mipple is the Princess of Hope. Porun and Lulun are the Prince and Princess of Light. All four used to live in the Garden of Light with the twins.
Zakennas are the enemies that the group encounters at first,with no-one seen controlling them. Zakennas are dark purple, shadow-like creatures of darkness, usually summoned by the Dark Zone. They can posess both people and items, although humans are very rarely being taken over by a Zakenna.
The Zakennas originally are sent out by a small group of dark beings from the Dark Zone, who are similar to the Seeds of Darkness because they are all that is left. They aim to destoy the powers of hope and light in order to conceal the only threat there is to their goal. They aim to destroy the worlds and fill them with darkness, thus trying to resurrect the Dark King.
Later on, the most powerful members of the group send out Fusions, which can take the form of any dark creature (Zakenna, Nightmares and monsters of Eternal). In fact, the Boss behind all this is revealed to be a Fusion that resembles a fused form of the Seeds of Darkness, as it has been after the twins ever since they were babies.