In the city of Antropolis, a drill for a new underground Metro Line project reveals strange creatures called Jumpers from within the planet that abduct the crew. Hero Factory send in Evo to investigate, which leads to an attack on the city by giant beasts. The Alpha 1 Team is flown in to stop the monsters by building battle machines to combat the beasts. Breez discovers that the monsters communicate with each other, while Stormer and Furno get abducted by the Jumpers. The remaining Heroes build more battle machines to explore the underground tunnel, while reinforcements from Hero Factory take on the Jumpers in the city above. After much exploration, the team arrive in the hive nest and discover their missing teammates hidden in cocoons in the custody of the Queen Mother of the beasts, who calls for more Jumpers and beasts to fight in her aid. Surrounded, Breez talks to the Queen and convinces her to free the other Heroes and let them all leave. However, the accidental death of one of the monsters causes the Queen to turn on the Heroes, forcing them to attack her. The pillar containing the nest collapses during the fight, crushing the Queen and sending the larvae falling into the lava. The Heroes escape to the surface where the tunnel is resealed, keeping the monsters inside. The Heroes head back to the Hero Factory, unaware of a Jumper cocoon hidden away in the loading deck of the Hero Craft.
