The strange deaths of several astronomers, left bleached white, pose a problem. Whilst Steed joins the stargazers, Emma chases a bright light, and finds herself in the hot seat.
Quest roles:
Philip Locke(Primble), Jeremy Lloyd(Bertram Smith), Barbara Shelley(Venus), Jon Pertwee(Brigadier Whitehead), Derek Newark(Crawford), Adrian Ropes(Jennings), Arthur Cox(Clarke), Michael Lynch(Hadley), Kenneth Benda(Mansford)