Brad Ingelsby Creator, Executive Producer, Screenwriter Kate Winslet Mare Sheehan Actor, Executive Producer Julianne Nicholson Lori Ross Actor Jean Smart Helen Actor Angourie Rice Siobhan Sheehan Actor Evan Peters Detective Colin Zabel Actor Guy Pearce Richard Ryan Actor Cailee Spaeny Erin McMenamin Actor David Denman Frank Sheehan Actor John Douglas Thompson Chief Carter Actor Patrick Murney Kenny McMenamin Actor James McArdle Deacon Mark Burton Actor Sosie Bacon Carrie Layden Actor Joe Tippett John Ross Actor Neal Huff Father Dan Hastings Actor Izzy King Drew Sheehan Actor Cameron Mann Ryan Ross Actor Kassie Mundhenk Moira Ross Actor Gordon Gray Executive Producer Paul Lee Executive Producer Gavin O'Connor Executive Producer Mark Roybal Executive Producer Craig Zobel Executive Producer