19. Spartan

Complete story — includes the ending

With the Ninth Circle after a Department of Defense vault drive, Diggle contacts his stepfather, General Roy Stewart, but Stewart refuses to give up classified intel. After they steal Archer from Smoak Tech, Stewart reveals the drive contains an asset list the Ninth Circle can now track. While securing the assets, Diggle and Stewart are captured by Dante. Stewart surrenders codes for a biological weapon called Cygnus X-1 when Dante starts torturing Diggle. The two call in Team Arrow with the Spartan helmet and escape. Team Arrow tracks Archer and the Ninth Circle to Cygnus X-1. While the rest destroy Archer, Oliver confronts Emiko, telling her Dante had her mother killed. Dante exfiltrates Emiko and they escape with Cygnus X-1, after which Emiko kills Dante. Diggle makes amends with Stewart after learning he is blameless in his father's death. Alena copied Archer's root code and suggests a partnership with Magnus Labs to expand it, but Felicity refuses to rebuild it. In the flashforwards, Mia and Connor obtain a power module for the tech helmet from the Deathstroke gang, led by Connor's adoptive brother John "J.J." Diggle Jr., but are afterwards attacked by them. Felicity powers up the helmet and learns Galaxy One has expanded Archer.