EXPLOSIVE SECRETS (4) by Valerie Hansen: A murderous gang believes Nicki Johnson knows a “secret code” thanks to a cryptic message her cousin relayed right before she died. Nicki swears that she has no idea what her cousin meant by her comment. K-9 Unit cop Jackson Worth believes Nicki is hiding something, but he vows to protect her. Nicki was burned by her ex, who left her pregnant and alone, and she is afraid to allow herself to love again. Jackson is dealing with PTSD and has created a wall around his heart. Can they allow themselves to let down their guard? This book continues the series that honors the heroic deeds of K-9 units, in a quick, intriguing read with a few twists and turns along the way.