Star Trek II is a very satisfying space adventure, closer in spirit and format to the popular TV series than to its big-budget predecessor.
Story is nominally a sequel to the TV episode Space Seed , with Starship Reliant captain Terrell (Paul Winfield) and Commander Chekov (Walter Koenig) incorrectly landing on a planet on an exploration mission. This allows the evil Khan (Ricardo Montalban) who was marooned there with his family and crew 15 years before by Kirk (William Shatner), to take over the Reliant and vow revenge on Kirk.
Admiral Kirk is coaxed to take command once again of the Starship Enterprise on a training mission, travels to the Regula space station on a rescue mission. Dr Carol Marcus (Bibi Besch) and her (and Kirk’s) son David (Merritt Butrick) have been working there on the Genesis Project, to convert barren planets into Eden-like sources of life. Khan has stolen the Genesis Effect equipment.
Final reel is a classic of emotional manipulation: Spock unhesitatingly calculates that he must sacrifice himself to save the Enterprise crew.