MIDNIGHT CALLER (4) by Diane Burke: Detective Tony Marino meets single mom Erin when her 5-year-old son, Jack, who suffers from cerebral palsy, wishes for a temporary dad to go with him to Disney World. Tony steps in and is soon strongly drawn to Erin and involved in her family life. When her best friend goes missing and is the suspected victim of a serial killer, Erin appears to be the next target, and Tony vows to keep her safe. Burke's solid mystery has characters who are easy to empathize with. There's some sadness, and the time spent with the psychotic killer is disturbing, which makes for a story not easily forgotten.