Arrow season 6, episode 4 synopsis: "Deathstroke Returns"

Episode released on November 9, 2017 and got 1.29 million views.

Slade asks Oliver to help him find his son, who's being held in jail. The two meet up with an old acquaintance of Slade, who provides them with the information they need. When they get to the prison, Slade instructs Oliver to find his son, Joe, then get him out of there, as he knows Joe will not want to see him, despite Oliver's objections. Slade engages the security, known as the Jackals, in combat, where he discovers his acquaintance is actually a member of them. When Slade demands they release Joe, he reveals it's not that easy as their boss is Joe himself. Dinah saves a politician from a sniper attack by Vigilante, as the politician supports the Anti-vigilante bill. Dinah later saves her again, and unleashes her Canary Cry on Vigilante who removes his mask, revealing he is actually Dinah's old partner Vincent Sobel, thought long dead. He later attempts another assassination attempt at a TV interview, but is once again met by Dinah and shot in the head by an officer. Vincent reveals the Particle Accelerator changed him as well, and claims he didn't tell Dinah he was alive, as he believes their work as cops had become ineffective. Dinah allows him to flee.