Ep 4. Red Light, Green Light

In "Elementary" season 7 episode 4, titled "Red Light, Green Light," Sherlock and Joan are hired by the NYPD to investigate a complex cyber-terrorism case. The case involves a string of deadly car accidents, and the authorities suspect that the accidents may have been caused by a hacker who is controlling the traffic signals around the city.

As they begin their investigation, Sherlock and Joan are shocked to discover that the hacker behind the attacks is none other than Odin Reichenbach, the billionaire tech magnate and longtime nemesis of Sherlock. It soon becomes clear that Reichenbach is using the attacks to further his own sinister agenda, and that he will stop at nothing to achieve his goals.

As they delve deeper into the case, Sherlock and Joan are forced to confront some uncomfortable truths about Reichenbach and his motivations. They must also grapple with their own feelings and past experiences with the man, as they race against the clock to track down the hacker and put a stop to his deadly scheme.

Throughout the episode, viewers are treated to the usual combination of high-stakes drama, intellectual puzzles, and witty banter that has made "Elementary" such a beloved show. Along the way, the episode also explores themes of power, control, and the complex relationships that can develop between people with vastly different backgrounds and motivations.

Ultimately, "Red Light, Green Light" is a gripping and satisfying addition to the final season of "Elementary," bringing the beloved characters and their stories to a thrilling and emotionally resonant conclusion.