Texas Rangers in Action #16

In "Assailant Unknown," Rangers Leo Shanz and Rand Beeman set a trap to catch six owl-hooters who have been terrorizing the area, but when the suspects surrender their gun during the confrontation, Arnell—a mysterious figure with a hidden agenda—arrives and complicates matters by revealing that Beeman may have been involved in a past incident. The story escalates when it's discovered that Arnell has connections to a decades-old swimming incident involving a boy named Bill Calder at the Rio Grande, forcing Beeman to confront a long-buried secret from his past that involves a promise he made to protect someone years ago.