Oliver must deal with the fallout of the explosion on the island.
Oliver tries to balance being the mayor, the Green Arrow and a father to William; Anatoly returns to Star City with a deadly agenda.
A rogue team led by Onyx breaks into Kord Industries and steals something lethal; Oliver struggles to connect with William, so he reaches out to a surprising source for help.
Just as Oliver starts getting things in order, Black Siren launches another attack on Star City.
Slade returns and asks Oliver for help tracking down his son; the rescue mission gets complicated by a terrible revelation that could shatter Slade's hopes of reunion.
Slade continues to uncover clues about his son's last few years; Oliver makes a big decision; the Green Arrow leads the team into battle against "The Dragon," a villain stealing valuable technology in Star City.
Oliver celebrates Thanksgiving with his family, but Black Siren interrupts when she returns to wreak havoc on the holiday.
Barry and Iris' wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony.
When Black Siren and Cayden James kidnap Quentin Lance as part of a plan to trade his life for a weapon of mass destruction, Oliver and his team must figure out a way to save Lance while still keeping the city safe.
Oliver discovers one of Cayden's secrets; he decides to team up with an unlikely ally to defeat him; Dinah spends time with Vince.
Cayden James launches his plan to take control of every aspect of the city; Oliver is determined to foil it with just the original Team Arrow; things get complicated when William is endangered as a result of Cayden's handiwork.
Oliver continues to battle Cayden James; when Dinah and Oliver have a major disagreement, one of their own is put in danger.
Cayden James discovers a secret about the Green Arrow; Oliver must decide if he needs to turn to his old teammates for help; William starts to demand more of Oliver's time.
Oliver, Diggle, and Felicity disagree with Dinah, Curtis, and Rene on how to handle Black Siren; the two teams face off, and a fight ensues.
Oliver and Thea are shocked to hear that Roy Harper is back in Star City; Black Siren makes a shocking decision.
Nyssa Al Ghul returns to warn Thea that some renegade League of Assassins members are planning to attack her; Athena is intent on finding a mysterious box that Malcolm left behind; Nyssa helps Oliver come to a life-changing realization.
Oliver and Diggle face their biggest challenge yet; Curtis is disappointed to find out his new boyfriend has a firm anti-vigilante stance.
In his darkest place yet, Oliver wonders if he has failed at everything; Oliver lashes out at Felicity and William; a surprising visit from an old friend has Oliver questioning his next move.
Looking to expand his empire, Diaz meets with The Quadrant, a coalition of mafia families; after Oliver's recent decision, Felicity and Curtis double their efforts to build Helix Dynamics.
Oliver turns to an old friend to help battle Diaz; Rene is out of the hospital but has a hard time readjusting to life as Wild Dog; Lance discovers something shocking about Black Siren.
Oliver begins to wonder if he will lose everything in his battle to save Star City; a familiar face returns.
Diaz targets Team Arrow and their loved ones; Felicity puts herself in danger when she gets a chance to stop Diaz for good.