Granite Oath

On a Thursday afternoon, Kat Serrano leaves work early, briefly returns to her remote trailer deep in Michigan's Upper Peninsula woods, and drives off with no explanation to her family. Two days later someone ransacks the trailer.
Kat is a Dreamer, and her mother won't talk to the police for fear she'll be deported and lose her 8-year-old granddaughter, Valeria.
Valeria is devastated by the events. She and her best friend from summer camp, Megan McCree, employ a "Pinky-swear" to get Megan's grandfather Seamus McCree to learn what happened.
Seamus uncovers a tangled web of drugs, prostitution, and dummy corporations, and soon finds himself the target of killers. Anyone sane would wash his hands of the mess or turn it over to the police.
But Seamus has given his word, his granite oath, to learn the truth . . . even if it kills him.