How Is Oliver In Central City On 'The Flash'? This 'Arrow' Crossover Timeline Is Getting Confusing

A few familiar faces are stopping by Central City for Tuesday's episode of The Flash. Not only will we see the return of Captain Cold and Firestorm, but the Arrow shows up as well. It's awesome that Barry Allen has so many strong and powerful friends, so I hate to bring this up, but shouldn't Oliver Queen be in Nanda Parbat? Shouldn't he be like, leading the League of Assassins or something? How is Oliver on The Flash , considering that the storylines on Arrow show that this guy has gone dark? The latest Arrow and Flash crossover , "Rogue Air," can't be about Oliver enjoying a day off from the League of Assassins, so I'm just trying to figure out how can still serve as a lifeline for Barry.

For the most part, the storylines on both The Flash and Arrow have coincided. Remember, that insanely awesome two-night crossover, when the events of each series directly impacted the other? It's happened a few other times, too — like when Felicity and Ray showed up in Central City, and then Cisco and Joe did some investigating in Starling. For most episodes, we can bet that the events in the two cities are happening on the same timeline. But for "Rogue Air," that might change.

While it's hard to figure out the specifics, it seems like this episode of The Flash takes place either before Oliver joined up with the League, or after he leaves (because he has to leave, right?). Both scenarios make sense. The Flash could be a few episodes behind the events on Arrow at this point, leaving Oliver free to head over to Central City and help Barry out. Or this could all happen after Oliver gets back (and OK, that's not completely confirmed at this point, but the trailer for the last episode suggests that he is not in Nanda Parbat anymore). Previews also reveal that Barry shows up in the next Arrow episode, so there's a lot going on in this timeline.

I doubt the League of Assassins has built-in vacation days for its members, so I think it's still really doubtful that Oliver leaves Nanda Parbat temporarily to fly back to Central City and lend Barry a heroic hand. But then again, check out his vigilante costume du jour in the "Rogue Air" still below. That's not his normal Arrow street attire — it looks more like something a League member would wear.

Maybe I'm completely wrong and you can take time off from the League. Then again, this could be something like "the enemy of my enemy is my friend." The League is everyone's enemy, and that includes Harrison Wells, too. They'd more than likely be up for snuffing him out, just so they don't have to deal with him later. So maybe Oliver's journey to Central City is endorsed by the League, and he can turn in all his travel receipts once he's back.

Having Oliver show up on The Flash right now — whether part of the League or not — makes sense. He has Barry's back no matter what, and now that it's time to fight the Big Bad, of course he makes an appearance. Even though he's gone a little off his rocker lately, deep down, Oliver is still a good guy.

Images: Diyah Pera/The CW (2)