Ester dan ibunya sedang membuat sarapan di dekat perbatasan AS/Mexico. Suatu malam, dua tamu tak diinginkan tiba, mengancam keselamatan semua orang. Tapi kedua wanita itu menyembunyikan Rahasia, salah satu yang dapat membuktikan yang paling berbahaya dari semua.
Coyote Lake is a reservoir on the Rio Grande along a dangerous drug smuggling route that has become synonymous with cartel violence and mysterious disappearances. It is there, on the lake, that Teresa and her seventeen-year-old daughter, Ester, run a boarding house where they routinely drug, rob and drown the unsuspecting drug-runners and human traffickers who stay the night. Teresa justifies the killings to her daughter, claiming they are ridding the world of bad people and saving the stolen money to leave Coyote Lake and start anew. But when they are taken hostage themselves by two intruding cartel gangsters, their dark routine is interrupted.