In the first of a two part episode, Horatio once again has to tangle with his ex, Julia, who has it out for him. Someone is out for Calleigh, and is compromising their investigation in the process.

In the second part of the two part episodes, Horatio deals with his past and the rest of the team works to rescue Calleigh from kidnappers.

As the first new medical examiner they have is shot, the CSIs learn the streets of Miami got more dangerous. Horatio must keep his team alive and restore order to his son's life. The clock runs out when one of their own is gunned down.

The evidence on who shot Horatio leads the team to some of most Miami's dangerous including one of their own.

A murder case involving extreme plastic surgery leads Horatio to Ron Saris, who is alive and seeking revenge on Julia.

The CSIs investigate the case of a man boiled alive, Julia spirals out of control, and one of the team's darkest secrets comes to light.