Carey Mulligan swaps period garb for a badge in “Collateral.” A trailer has dropped for the four-part crime thriller. The Oscar nominee plays Kip Glaspie, a detective determined to find answers when a pizza delivery man is gunned down in London. Written off as a random act of violence by some, the crime leaves Kip convinced that there’s something more at play: The only witness leaves a false name and address, and the victim’s last customer (Billie Piper) is the ex-wife of a well-known politician (John Simm).

Little is revealed about either the crime or Kip in the spot. “I’m trying to guess what kind of person you are,” the politician tells her. We’re also left wondering the answer to that question.

S.J. Clarkson directed every episode of the series. She’s previously directed eps of “Jessica Jones,” “Orange is the New Black,” and “Dexter,” among many other shows.

“There are lots of wife and girlfriend parts [in film] where the male protagonist is driving the story,” Mulligan observed while promoting “Collateral.” “You’re just aiding the performance of the man who is the great inventor or politician or superhero saving the world, and you’re there going, ‘I’ve baked you some banana bread, darling.’ I just don’t find those parts interesting. I want to be the great inventor myself.”

Mulligan’s recent credits include post-WWII drama “Mudbound,” women’s rights story “Suffragette,” and an adaptation of “Far From the Madding Crowd.” She scored raves out of Sundance in January for her performance in “Wildlife.” The pic takes place in the 1960s and follows a boy who witnesses the dissolution of his parent’s marriage. She’ll re-team with “Mudbound” director Dee Rees for “An Uncivil War,” a drama about Gloria Steinem’s fight to ratify the Equal Rights Amendment.

“Collateral” premieres tonight on BBC2. The show will be released internationally on Netflix.