BattleTech: The Animated Series - Season 1 Episode 4 Retribution

The show begins with the ruined world of Romulus. Nicholai finds Cero, chooses to take him as his bondsman due to his nobble birth. He also believes the planet to be conquered and wants to move to other worlds. Stiener and his strikers are in the tunnels, low on ammo and in need of repair. They meet up with the remains of the Romulus malitia. They plan to hit an ammo depot. The mechs move through the tunnels, and upon exiting they meet five toads. They enter the tunnels again and come up with a plan. Nicholai tries to brainwash Cero and gain information about his affiliation. Sakamoto and the crew of the dropship take control of their captors and escape. The mechs lead the toads into the tunnels, split up, and lead the toads to an abandoned mech on self destruct.