Mark Ruffalo already has a Black Widow solo movie planned out

Everything's in place - now, seriously, what's stopping Marvel from making this a reality?

Marvel are absolutely on top at the moment; delivering the momentous, emotionally-driven thrills of Captain America: Civil War, while setting up an absolutely tantalising slate of upcoming films.

Yet, fans are still thrown by a notable absence in that schedule: where, oh where, is Black Widow's solo film? The fans want it, Civil War's directing duo the Russo brothers want it; even Marvel Studios head Kevin Feige wants it.

In fact, Mark Ruffalo wants it so much, that he's gone and done the hard work by drafting up a pretty irresistible pitch for the film. And who would say no to this plot?

"I'd like to see her whole beginning story that we hear about [in Avengers: Age of Ultron]," Ruffalo told Digital Spy, referencing the scene in which Scarlett Johansson's Natasha Romanoff reveals her dark past to Bruce Banner. "It's so fascinating, her being raised from the very beginning as just a killing deception machine, and how she comes to be with [the Avengers] and how she finds her morality. It would be amazing."

So what are we waiting for, again? By Marvel's own working logic, it's almost unconscionable that Black Widow has yet to receive a solo outing; not when she's proven such an indispensable asset to the franchise.

Ever since her sly introduction in 2010's Iron Man 2, Natasha Romanoff has rapidly developed into a fan favourite, as well as one of the most crucial emotional load-bearers of the franchise; due, specifically, to the fact there's so much of her story yet to be told. She's a mystery, an engima; whose brief moments of vulnerability open the door to a world of secrets aching to be set free.

Sure, we're drifting here from the traditional superhero punch-ups into the espionage genre's steel-cut thrills with Ruffalo's description; but Marvel's already starting to acknowledge that the comic book film is an entity in the midst of mutation, with the Cold War thriller touch to Winter Soldier an apt preview of exactly what a Black Widow film could be.