A teenage girl makes a startling discovery about her connection to the Seawalkers, legendary beings who are half-human, half-sea creature.
| Actor | Role |
|---|---|
 Emily RuddMiranda Merchant | Miranda Merchant |
 Keenan TraceyTJ | TJ |
 Skyler MaxonLeo | Leo |
 Maria DizziaAmelia | Amelia |
 Sarah PowerKit Morgan | Kit Morgan |
 Siobhan WilliamsGinny | Ginny |
 Gabriel HoganRamsay | Ramsay |
| MMalia RogersKate | Kate |
| JJordan JeremiahJake | Jake |
 Bernard RobichaudBobby Senior | Bobby Senior |
| MMatthew McIntyreDave | Dave |
 Naomi GaskinLeanne Cooper | Leanne Cooper |
| LLaura KohootNan Cunningham | Nan Cunningham |
 Taylor RussellCece | Cece |
 Zoé De Grand MaisonNaomi | Naomi |
 Justin KellyBobby | Bobby |
 Jo VannicolaNick Colley | Nick Colley |