Three Robot Knights

Three Robot Knights ("Robotto sanjūshi" ロボット三銃士) is an episode of the 1963 Astro Boy anime series.

Synopsis
In order to save patients suffering from space disease on Mars, a serum is sent to Mars from Earth. All the transport ships carrying the serum, however, get destroyed on their way. Astro, together with the three robot knights, goes into space to protect the last of the serum.

Characters
In Order of Appearance: