From publisher blurb:
Welcome to the Sentinels!
The Sentinels Agenda is a program overseen by CASTLE (the "Committee of Advanced Strategy, Technology, and Law Enforcement") to bring together extraordinary individuals to deal with impossible problems. It's had a revolving membership over the years, but began with a core of two CASTLE agents, Knight Ranger (expert archer), and Red Widow (covert agent). Iconic Legends. Because sometimes you a need a character everyone knows, even if they're meeting them for the first time.