The title refers to April 29, 1986, the day that German television aired Swan Song (1985), the Season Eight finale of Dallas (1978) in which Bobby Ewing (Patrick Duffy) was killed by his sister-in-law Katherine Wentworth (Morgan Brittany). The Chernobyl nuclear accident had occurred three days earlier.
The town "Wattstedt" shown in the film as home of the NPP is in fact the town Brokdorf, Germany, which in the late 1970s and early ;80s was a center of anti-nuclear-power demonstration in Germany.
Niels was born in 1969.
The film takes place in April 1986.