After leaving Proto Dome, Crono and his party enter the Factory, but Robo has to deactivate the security systems first. They then travel deep into the Factory battling robot enemies and using security codes to access different areas. One important code is XABY.
They finally restore power to Proto Dome. But upon their exit from the Factory, they are confronted by the R Series of robots. The six R Series robots inform Robo that he is defective, which is why he is helping humans and fighting against his own kind. So the R Series destroys Robo. The two remaining party members battle the R Series and defeat them. They then take Robo back to Proto Dome where Lucca repairs him once again.