It is now on the distant planet Solaria that Elijah Baley and R. Daneel Olivaw will exercise their investigative talents. In this world, men no longer agree to meet physically but “view” each other through television projections. However, a murder has been committed, a murder apparently impossible since no Solarian would have enough courage to approach one of his compatriots. What's more, everything seems to indicate that a robot is involved. Absurd ! The Laws of Robotics prohibit these artificial beings from causing the slightest harm to humans...