Explorers of the Hero's Ruin! (Japanese: 黒き英雄の遺跡！シンボラーとデスカーン！！ Hepburn: The Black Hero's Ruins! Sigilyph and Cofagrigus!!) is the 16th episode of Pokémon: BW Rival Destinies.
After the events of the last episode when Bianca leaves the group behind her, Cedric Juniper came out of the cave in bad shape and collapsed. After he feels better, Cedric officially introduces himself and explains what happened. Apparently he found some ruins and needed help to investigate. Ash and Iris were more than excited to help when they found out the temple had a link to the legendary Pokémon Zekrom by the hero as so as his heart becomes one with the Pokémon. As they make their way through various trap sets as Cedric explains his rules, they've got themselves into trouble when they see one Sigilyph blinded with anger when Cedric took the Golden Dark Stone and encountered a lot of Cofagrigus ambushing out of hiding. Will our heroes survive the ordeal?
Juniper's father recovers, while her daughter explains the heroes he is a researcher specializing in Legendary Pokémon. Juniper's father informs them of the discovery, as he learned of a ruin where a hero contacted Zekrom, but a cave got in his way. Prof. Juniper gives her father the pen she found stuck on a Klinklang, making her father inspired to visit the caves once more. The heroes decide to accompany her father to visit the ruins. The heroes ask if they can come, but Juniper's father, Cedric, stops them and thinks a bit, then accepts, as Juniper tells he has a habit of finishing sentences a moment later. The heroes wave Juniper farewell and go with Cedric through Chargestone Cave and across the land.
At night, the heroes ask Cedric to recite the story of the hero. Cedric stops a bit and tells them the story from mythology. He tells them when the hero turned darkness into light, his heart would be one with the Pokémon, causing Zekrom to descend. The heroes are amazed, while Cedric replies he would like them to learn a bit and have fun as well. Next day, Cedric leads them to the ruins, but warns them there may be traps ahead. They come to a dead end, where a statue of a Venipede lies inside a space. Cedric senses a trap and reads an ancient text that tells of turning the statue to the left. Cilan does so, but right before Cedric finishes the translation revealing would be a bad idea. Soon, they run away from a giant boulder. Cilan sends Pansage, who digs a hole, so the heroes enter it and save themselves. Cedric advises them to let him finish the thought before acting.
Still, Cedric points out with the boulder out of the way, the passage is cleared. They come to two bridges. Cedric reads the bridge to the right is the wrong one. Cilan and Ash assume the left one is correct one and take it. However, Cedric reads that one is also wrong, as Ash and Cilan hang on it. Later, with Ash and Cilan rescued, Cedric advises them not to assume anything. Cilan thinks even if they were to cross the bridge, the cave would also be a trap. Axew finds a way, which the heroes take it.
Soon, they are at three different paths. They go into Darumaka cave, but are trapped by two walls of fire. Cilan sends Stunfisk to use Mud Bomb, which douses the fire. They return and go into Krokorok cave. They come to a dead end, and soon the walls begin moving. Iris sends Excadrill, whose Metal Claw holds the walls. Once the heroes are out, Iris calls Excadrill back and go to the Golett cave. Cedric admits he knew that was the correct path, but did not say anything, for he wanted to offer the heroes some excitement. Iris is not pleased, but Ash thinks Cedric is right and head to the Golett path. They come to a room with four sarcophagus. As they continue, one opens to observe them. They come to a door and push it, only to reveal a flashing light. They enter the room and see it is shaped like a volcano. They come to the bottom, seeing some glowing crystals. Cedric believes this is the place where the hero contacted Zekrom.
Ash notices a glowing orb, but Cedric stops him, for it is the Golden Darkstone. He suspects this is what was used to summon Zekrom, hence why it must have a dangerous trap, thinking they may not come out alive if they trigger it. Cedric advises them not to activate such traps, as this is as far as they go. The heroes hoped they could see Zekrom, but Cilan reminds them they experienced adventure. Suddenly, a Sigilyph appears, who uses Psybeam. Pikachu uses Thunderbolt, but Sigilyph dodges and uses Mirror Move, hitting them back, then puts Pikachu to sleep with Hypnosis. The heroes are hit by Psybeam, so return and hide in sarcophagus. Sigilyph goes away, but Cedric, Ash and Cilan see Iris is not out yet.
They open the sarcophagus and are shocked a Pokémon, Cofagrigus, comes out. They demand Iris back, but Cofagrigus takes control of Ash and Pikachu. Cilan sends Pansage, who digs and hits Cofagrigus, who uses Will-O'-Wisp. Pansage dodges the attack and uses Solarbeam, knocking Cofagrigus out. Soon, Iris and Axew come out, wrapped in bandages and take them off. A door opens, so they all go through it. However, they encounter more sarcophagus, from which more Cofagrigus emerge. They continue to run, but are pursued by Sigilyph, who chases them using Psybeam. The heroes wonder why are they being attacked, so Cedric shows them the Golden Darkstone, for he couldn't resist not to take it.
Cedric thinks they need to return it to calm down the anger. However, Cofagrigus control them and send them through another door, in which they fall down into an underwater lake. Cedric admits he took the stone on purpose, as, by legend, the hero encountered Zekrom beneath the surface. He raises the stone, causing glyphs to glow, revealing the legend. He explains the hero was injured and fell down beneath the surface, where he summoned Zekrom to save him from the darkness. Ash thinks they need to find a way out, but Cilan sees no possible exits. Cedric advises them never to give up and thinks they need to find possible exits.
After searching a bit, they open the door and are back to the place where Sigilyph attacked them first. Cedric places the stone back where it resided, but Sigilyph and Cofagrigus return. They control then and send them flying into air, then fall down. Cedric advises them the solution to these dangerous problems lie in the legend's core. The heroes remember the hero was saved because his heart was one with the Pokémon. The heroes remember their past adventures with the Pokémon. Soon, their free fall is slowed down by Cofagrigus and Sigilyph, who save them. The heroes thank them, while Cedric advises them if they combine odd facts, they can lead to new discoveries. He traced the path they took and realized it forms Zekrom's outline.
Ash and Cilan had a great time, while Iris is skeptical. Cedric decides to research the ruins further, then bids the heroes farewell, as they go on their own directions. Suddenly, the heroes encounter the Sunglasses Krookodile, who has a grin on its face.
- Who's That Pokémon: Cofagrigus (JP), Sigilyph (US)
- The soundtrack title theme of Zoroark - Master of Illusions is played in this episode.
- There were three cave entrances each with the head of a Darumaka, a Krokorok and a Golett. Like the movie called The Great Escape, there were three tunnels that are similar to the ones they've picked. The tunnels in the film that are similar are "Tom", "Dick", and "Harry".