Seventy-two guns are stolen from a San Francisco police storage facility, causing murders in the city to spike. The shooters appear unrelated—their only connection is that each uses a gun stolen from police storage. The police have no leads.

Mei Ling, recently brought in as head of the SFPD's Computer Forensics Team, recognizes a device installed in the same storage facility—one used for hacking. She's convinced this could be a new connection to help crack the case. But how?

When the bullets start flying through the window of her own home, Mei knows she's on to something. Now it's a race against time to identify the hacker.

Before she becomes the next victim.