Our heroes have been invited by Professor Juniper’s father, Professor Cedric Juniper, to join him as he explores a ruin said to be the site of a meeting between an ancient Hero and the Legendary Pokémon Zekrom.

When they arrive at the ruin, Cedric warns our heroes that it may be filled with traps, and he’s absolutely right! A huge boulder rolling down a narrow passageway threatens to mow them down, but Pansage uses Dig and our heroes escape to safety. Then they encounter two bridges spanning a deep gorge, and assume one of them is a trap—but it turns out both bridges are fraught with danger! Axew manages to find another way around the chasm, and our heroes move on.

Next, they encounter three cave entrances, each painted to look like a Pokémon: Darumaka, Krokorok, and Golett. They try the Darumaka cave first, then the Krokorok tunnel, but both are full of traps yet again. Cedric then reveals that he knew the Golett cave was the right one the whole time! He kept it to himself because he wanted the youngsters to get “the full enjoyment” out of their adventure. Ash thinks that makes Cedric super cool, but Iris is somewhat less appreciative...

The Golett cave leads to a large room shaped like a volcanic crater, where they discover a circle of huge crystals and an artifact known as the Golden Dark Stone. Cedric warns our heroes not to touch the Stone, but after they’re attacked by an angry Sigilyph and a group of Cofagrigus, he reveals that he grabbed it when they weren’t looking!

When all seems lost, Cedric reminds them of the Legend of the Hero: “Zekrom lent its power to the Hero as soon as his heart became one with the Pokémon.” Ash and his friends think back on all the wonderful times they’ve shared with their Pokémon, and that seems to be enough to satisfy the ruin’s guardians, as Sigilyph and Cofagrigus stop attacking our heroes and rescue them instead.

Although Iris is annoyed at the dangers their adventure presented, Ash and Cilan are ecstatic about all the fun they had. They thank Cedric and bid their new friend goodbye to continue their journey. But before they get very far, they come face to face with a menacing Krokorok in sunglasses...