The brutal murder of a French citizen sees French homicide investigator Kahina Zadi (Leïla Bekhti) go to Kiruna, Sweden. Together with Rutger Burlin (Peter Stormare) she begins an investigation that soon takes on staggering proportions.

A mother sends postcards to her estranged son and daughter inviting them back to the guest house they grew up in. She gives each of her children one piece of advice and leaves them to ponder the meaning.