Walk Away: Camaro Espinoza Book 2 by Sam Hawken
Camaro Espinoza is 'the deadliest female protagonist since Jon Land's Caitlin Strong and Stieg Larsson's Lisbeth Salander' (Booklist).
Former combat medic Camaro Espinoza is trying to put her past behind her. She knows she's done bad things - but they were always for good reasons.
Then her calm, anonymous life is interrupted by a distress call from her sister Annabel. She's become trapped in an abusive relationship with petty criminal Jake Collier, and she needs Camaro's help.
Camaro has always protected Annabel, and she won't stop now. But the situation is more dangerous than she realises. Jake has a sibling of his own, an ex-Marine named Lukas who is as unhinged as Camaro is uncompromising. And he and Jake are planning a much bigger crime.
As the federal marshals pick up Lukas's trail, and a bounty hunter with a debt to settle closes in, Camaro's smart enough to know that standing her ground is the last thing she should do. But even with a freight train like Lukas barrelling towards her, if there's one thing she can't do, it's walk away.