SPOILER WARNING: This article contains major spoilers for "Deathstroke Returns," the latest episode of Arrow.
In "Reversal," last week's episode of Arrow, Deathstroke called Oliver Queen to ask for help finding his son Joe Wilson. Now, in "Deathstroke Returns," Oliver agreed to help his frenemy -- even if it meant travelling halfway around the world to Kasnia in order to do so.
According to Deathstroke, his son had enlisted in the Australian military agency A.S.I.S. to follow in the footsteps of his father, only to land in a Kasnia prison. In order to avoid violence, Slade wanted Oliver to accompany him so that they could pursue a diplomatic option for his release. However, when they got there, they were informed Slade's son -- going by the name Kane Wolfman, in tribute to Deathstroke co-creator Marv Wolfman -- had been killed in a prison fight.
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As they quickly discovered, that was a lie. Under pressure from both Oliver and Slade, the prison warden relented and admitted Joe had been taken away by a ruthless mercenary group called the Jackals. Since the Jackals were so powerful, no one went after Joe and he was assumed dead.
In response, Deathstroke went to hunt the Jackals down -- but not before drugging Oliver, so that he wouldn't break the promise he made to his son William. Alone, Deathstroke tore through the Jackals, killing a dozen or so men until he became outnumbered. However, the Jackals didn't kill Deathstroke, even though he was at their mercy, and the reason why soon became clear.
As Deathstroke howled at them about the death of his son, Joe Wilson himself sauntered into the room. As it turned out, Joe had neither been killed by the Jackals, nor was he their prisoner. In fact, he was their leader. The episode came to a close as Deathstroke faced his son, stunned.
"Deathstroke Returns" is the first part in a two-episode story arc. The storyline will continue -- and presumably be concluded -- in "Promises Kept," next week's episode. According to the episode description, Slade "continues to uncover clues about his son's last few years," which means we'll probably come to find out how Joe became the leader of the Jackals.
Starring Stephen Amell as the Emerald Archer (well, not currently), Arrow airs Thursdays at 9pm ET/PT on The CW. The series also stars Emily Bett Rickards, David Ramsey, Willa Holland and more.