Eve is a bored, whip-smart, pay-grade MI5 security officer whose desk-bound job doesn't fulfill her fantasies of being a spy. Villanelle is a mercurial, talented killer who clings to the luxuries her violent job affords her. Everything changes when they cross paths.

Eve is attempting to rebuild her life, having been shot by Villanelle. Villanelle is also moving on, until she is approached by an old foe. Carolyn is being undermined at work and Kenny can't leave his own investigation into The Twelve alone.

A terminally ill teen upsets her parents when she falls in love with a small-time drug dealer.