A teenager finds her perfect life upended when she's stalked by a mysterious doppelganger who has her eyes set on assuming her identity.
| Actor | Role |
|---|---|
 Sophie TurnerFay Delussey / Lila Delussey | Fay Delussey / Lila Delussey |
 Claire ForlaniAnn Delussey | Ann Delussey |
 Rhys IfansDon Delussey | Don Delussey |
| EEugenio PérezDoctor Carbantes | Doctor Carbantes |
 Gregg SulkinDrew Fraser | Drew Fraser |
 Priyanka PatelDawn | Dawn |
 Ivana BaqueroKaylie | Kaylie |
 Jonathan Rhys MeyersJohn | John |
 Charlotte VegaMonica Meldrum | Monica Meldrum |
 Geraldine ChaplinMrs. Brennan | Mrs. Brennan |
 Neil D'SouzaMr. Bhoola | Mr. Bhoola |
 Sara GregoryWoman with Baby | Woman with Baby |
| ZZita SattarMira | Mira |
 Sion Daniel YoungJoe, The Hooded Youth | Joe, The Hooded Youth |
 Daniel HawksfordPC Edwards | PC Edwards |
 Leonor WatlingMrs. Williams | Mrs. Williams |
| RRobbie BowmanMr. Reynolds | Mr. Reynolds |
| DDylan CharlesMr. Hardie | Mr. Hardie |
| AAmanda EdwardsPolicewoman | Policewoman |
 Melanie WaltersMrs. MacPhail | Mrs. MacPhail |