Mannix is brought to a small town in New Mexico on a ruse, and then subpoenaed to testify as an expert witness for the prosecution in a murder trial. After his testimony, the woman representing the defendant announces she wants to resign as defense counsel. Mannix decides that instead of returning to Los Angeles, he'll remain to aid the defense, encouraging the defendant's attorney to stick with the case while he tries to dig up new information that could free her client.
—aldanoli