Robot 7

(from ebookjapan):
One day, a young boy, Susumu Katagiri, witnesses a hit-and-run. The victim, an old man, entrusted him with a mysterious switch before he drew his last breath. It was "Call M", which can call a robot named "Seven"! Susumu is puzzled by the fact that Seven can only listen to the commands of the person who presses "Call M" and can be either evil or good, but he is attacked by a gang of people who are after "Call M." ......!? In addition to the title story, this masterpiece collection includes four short stories, including "Time Patrol".