This volume starts off with a common thug named Heller getting a hold of a gauntlet and using a Storm Patrol, a light-based creature dubbed Shaw K’Naw, to perform various robberies. Ray, Allie and Gabe go after the thief under the tutelage of Master Nigel Brightmore. Ray goes blind early in the attack and has to learn some of his other senses in order to win though. He also gets to know a new creature, a Dark Civilization Tarborg named Fumes.
This is followed by an episode where the kids spend some time bonding with the Nature master, Benjirou Kimora. When his creature, Mighty Shouter, doesn’t come when summoned, the group travel to the Nature Civilization. There, they learn that the Choten are capturing creatures and draining them of their mana for energy. When Ray and Tatsurion the Unchained are sucked into the prison, Ray must work to release the captured creatures and take down the Choten’s operation. Along the way, Kimora will start to see things a little differently as he gets to know Mighty Shouter on a new level. For Kimora, the creatures are no longer brainless animals to be commanded, but intelligent beings who should be reasoned with.
The next episode, "Duel Hard," is the prelude to a short story arc. In this episode, Alakshmi, Heller and Saguru rob a bank that is supposed to hold one of the greatest pieces of Water Civilization technology. It just so happens that Allie’s father is the bank manager and she and Ray stopped by just before the robbery. In a somewhat John McClane manner (thus the episode’s play off of the Die Hard films), Ray and Allie work to overthrow the Choten forces and hopefully get the piece of technology themselves.
Unfortunately, Allie’s father is taken and left in the Dark Civilization at the end of the heist. The last two episodes of the volume have Allie spearheading an incursion into the land to find and save her father. As she focuses on her goal, Master Jaha warns her that she maybe slipping too far into the darkness.
Like past volumes, Kaijudo: Rise of the Duel Masters: Darkness of Heart is light on special features. It comes with a card, "Memory Swarm" and the two on-disc bonuses are videos from the reveal of the trading card "King Tritonus" and the reveal of the all-foil Triple Strike Deck. All three extras are something that fans of the CCG will be interested in, but it’s hard to see someone who likes only the show getting too much enjoyment out of these added elements.
Oddly enough, the episodes aren’t being released in the order they were aired in. For the most part, nothing seems to be lost as far as missed references, but it still feels odd that they are releasing the episodes out of order. Anyway, this particular collection of episodes fit well together even if it isn’t the original order.