6. Due Process

Complete story — includes the ending

Diaz slaughters the Bratva and tortures Anatoly Knyazev in order to get in contact with one of his former KGB associates. Team Arrow rescues Anatoly and discovers that Diaz plans to level Star City with aerial explosives obtained from the associate. Team Arrow foils the plan and finally captures Diaz with help from the new Green Arrow. Meanwhile, in Slabside, Stanley Dover is accused of murdering a guard, but proclaims his innocence. Oliver finds the knife used in the attack, which belonged to Brick's associate Ben Turner. Released from solitary confinement, Stanley thanks Oliver, but inadvertently reveals knowing that the knife belonged to Turner, information he could not have gotten in solitary. At Star City Police Department (SCPD), Laurel orchestrates a deal which will see Oliver walk out of prison in exchange for helping the FBI with their case against Diaz. In flashforwards, Roy reveals that the clue they found on Lian Yu was the "Mark of Four," which Dinah recognizes. William and Roy learn that, before her apparent death, Felicity became a criminal, taking on her father 's mantle as the Calculator. They, along with Dinah and Zoe, find Felicity's plans for the destruction of Star City.