The film stars Aneurin Barnard as Tommy, a widower who must raise his baby alone after an attack by a gang leaves his wife dead and him suffering from agoraphobia.
Eight months later, Tommy is living in a run-down council estate, which is a little better than the tower block he vacated, and caring for his baby daughter Elsa.
At Joanne's funeral, Tommy meets a foul-mouthed and eccentric priest who warns him that the gang of feral teenagers will be back for his daughter.
Trying to calm him down, Marie disputes that the same gang were looking to kidnap his daughter, instead suggesting that he's simply the victim of two random, violent attacks by different groups of teenagers.
The children grew up alone, and eventually had an incestuous relationship, which resulted in the birth of a mutant breed, blind and feral, who "see" people by sensing their fear.
They go there with Danny, who uses his ability to prevent the ferals from sensing their presence, and proceed to wire the building with home-made explosives, but Tommy separates from the others when he hears a baby crying.
Writer/director Ciarán Foy based the film on his own experiences, including an attack by youths in hoodies, who threatened him with a dirty syringe.
[5] In a mixed review, Jeannette Catsoulis of The New York Times said the film "occasionally veers into ludicrousness" and has an "atavistic pulse".
[3] In a negative review, John DeFore of The Hollywood Reporter cited the overtones of class warfare and poor timing, given the killing of Trayvon Martin.
[6] In a more positive review, Roger Ebert rated the film 3 out of 4 stars, citing young people in hoodies as being inherently scary.
Club compared it to Roman Polanski's Repulsion, calling Citadel "a bare-bones man-against-his-worst-fears white knuckler, shot through deep, menacing shadows.
"[8] Joe Leydon of Variety wrote: "Writer-director Ciaran Foy skillfully taps into primal fears and urban paranoia to keep his audience consistently unsettled in Citadel, an intensely suspenseful horror-thriller.