The world is on lockdown due to a virus that originated in Miami. A woman is kidnapped from her apartment, and detective Harry Hunter is on the case. At the same time, his sister shows up after they haven't seen each other in a year. As it turns out, Harry's sister knows more about the virus than she lets on. Soon, he wonders if the virus is connected to the missing woman. As he digs deeper into the strange mystery, he realizes his sister's life is in great danger, and so is his. Never Walk Alone is the fourth book in the Harry Hunter Mystery series.