Alex has been captured and Tom, Kyra and Jack must scramble to find him. As Scorpia demonstrates the power of their new weapon, Invisible Sword, Alex is confronted by Julia Rothman with some uncomfortable truths about his father.

Alex is sent on a mission for Scorpia to prove his loyalty, with Tom and Kyra following close behind hoping to rescue him. Meanwhile, the Department attempts to unlock the secret of 'Invisible Sword'.