The 15th episode of Gerry Anderson’s space adventure series Space: 1999 premieres on British broadcaster ITV. 
Eagle 6 is launched to explore an Earthlike planet, but when the landing party doesn’t report back to Moonbase Alpha for hours, Koenig orders the ship returned by remote control…but Eagle 6 returns with no one aboard except for a dead caveman. A full-scale rescue operation is launched, with only three days to find the missing Eagle crew before the moon moves out of range. The rescue mission goes disastrously wrong, though – Commander Koenig and Dr. Russell go missing, along with the rest of their Eagle’s search party, while Carter is attacked by more cavemen when he lands a second Eagle and begins his own search for Koenig. Carter narrowly escapes being killed when the cavemen are too fascinated by his communicatior to deliver the fatal blow. Back at the Moonbase, the autopsy of the caveman turns up something very disturbing: he was originally a member of the first Eagle crew.
written by Jesse Lasky Jr. & Pat Silver
directed by Bob Kellett
music by Barry Gray
additional music by Vic ElmsCast: Martin Landau (Commander John Koenig), Barbara Bain (Dr. Helena Russell), Barry Morse (Professor Victor Bergman), Prentis Hancock (Paul Morrow), Clifton Jones (David Kano), Zienia Merton (Sandra Benes), Anton Phillips (Dr. Mathias), Nick Tate (Alan Carter), Oliver Cotton (Spear man)
LogBook entry by Earl Green