The Flash just revealed answer to Arrow's biggest mystery

John Diggle returns.

By Sam Warner

17 Jun 2022

The Flash spoilers follow.

The Flash brought in a huge tie-in to Arrow in its latest episode by answering a longstanding John Diggle mystery.

In this week's (June 15) season eight episode 'The Man in the Yellow Tie', Eobard Thawne (Tom Cavanagh) is visited by Diggle (David Ramsey) and his cube, revealing that he has spent years traversing the Earth trying to open the box once again.

The long-running storyline – or so-called Green Lantern arc – concludes in the episode, however, as Diggle first shares his concerns that if he manages to open the object, he could be taken away from all that he loves.

david ramsey as john diggle in the flash, season 7

Warner Bros.

"I can't leave it behind," he declares. "I can still feel it in my mind, pulling me closer. And the more I fight it, the louder I hear its call." He turns to Thawne as he believes he can help open it, the latter agreeing provided he can look into its contents.

Thawne explains that the cube "appears to people who are at a crossroads, a turning point in life", with Diggle burying Oliver McQueen and moving his family at the time he discovered it.

Diggle admits he's ready to accept its power and is told to put himself in the right headspace, imagining "all the light that you could bring into this world, all the cosmic odysseys that await... all the lives you could lead".

david ramsey as john diggle discovering the green lantern light in arrow finale

The CW

Sure enough, the cube re-opens, though Diggle quickly realises that he wants none of it, and throws the object down before it disappears into a void.

"I saw a thousand lives I could lead, but not one of them led me back to my family," Diggle confirms, as Thawne berates him for his choice and calls him "not special".

Diggle hits back: "But I am someone special. I now realize the cube was trying to make me someone else… something else. But there is no power in the universe more powerful than the love I have for my family."

The Flash airs on The CW in the US. Sky Showcase and NOW air the show in the UK.