Master of the House is the second episode of the Beast Machines TV series.
Underground, where the Vehicons have neglected to look, the four Maximals gather. Under the teachings of Optimus Primal, the team try to relearn their new transformations. However, it is no longer simple command codes, but now requires emotional balance and deep concentration since their reformatting at the hands of the Oracle. Cheetor and Blackarachnia manage to use their technorganic transformations properly, but Rattrap still has trouble with his new body. But their time in robot mode is limited, as a rumbling shakes the chamber and a Vehicon Mole attacks the Maximals. The shock has forced Cheetor and Blackarachnia back into their beast modes, and they take shelter behind Primal.
Optimus Primal leaps in front of the frightened Maximals and deflects the blasts, all the while explaining that they reverted because they lost their emotional balance. Primal destroys the mindless Vehicon with a blast of energy, but knows it's time to leave, hopefully to find a new base and continue their transformation lessons. However, his idea is met with mild rebuff by Cheetor and Blackarachnia. They believe that they should seek out any survivors and reformat them, using them to destroy the drones. But Optimus overrules them, saying they need to get a handle on their new transformations before they go out looking for trouble. They split up to search out a new base. Blackarachnia and Cheetor are paired together (real smart pairing them up, ya big munky), and Rattrap and Primal go the opposite way.
Cheetor and Blackarachnia (with some goading on Blackarachnia's part) decide to go topside. As soon as they clamber up from the caves, they discover that they are in Cybertropolis, the new capital of Cybertron after Iacon's size made it useless to the new population. But there is a problem; Cybertropolis should be home to "ten million Transformers", but the duo find it deserted, and the Cybertron InfoCore has been deleted.
Before the pair can investigate further, they are attacked by Aero Drones, and plunge off the side of a building before they can slide to safety. As he runs, Cheetor attempts to transform, but he hasn't found his spiritual center yet and remains in cat mode. Blackarachnia traps two of the jets with her webs, but more arrive. Fortunately, Optimus arrives. He quickly transforms into robot mode and takes to the air, but is soon overwhelmed.
Cheetor and Blackarachnia manage to transform, and they quickly dispatch the drones, Blackarachnia using electrical "stinger" energy and Cheetor's scimitars. Optimus scolds Cheetor for disobeying orders, but is intrigued at their findings. Optimus orders the group to head to the Council Citadel, hoping to find answers. Rattrap moves ahead of the rest of the group but encounters Tank Drones. Optimus orders Cheetor and Blackarachnia to hold off the drones while he investigates inside. When he gets inside, he heads to the chambers of the Maximal Elders.
Reaching the council meeting room, Optimus Primal comes face to face with the leader of the drones—Megatron, now encased in a suit of control armor. He greets Primal cordially, and decides to "fill in" the gaps in Primal's memory. Megatron claims that he won the Beast Wars, and that he decided to remodel Cybertron into his own image, one of technological purity, devoid of organic life. Thus, he explains, came the Vehicons, sparkless Transformers who will serve Megatron and crush Primal's "mongrel" Maximals.
However, the Maximals manage to survive the Vehicons, their technorganic bodies and spark-powered ingenuity foiling the mindless might of the drones. Frustrated by the Maximals' survival, and with some goading by Optimus Primal, the enraged Megatron breaks free of his harness and transforms into his dragon mode, deactivating the drones in the process. Primal and Megatron fight, but Megatron reconnects to his control harness, and summons more Vehicons, mocking Primal all the while. The Maximals arrive, and barely manage to drag Primal away.
When the Maximals inquire about what happened, Optimus Primal tells them that this all happened because he failed to destroy Megatron. However, it is now up to Primal to correct that mistake.