Only halfway through the third season of CW's superhero drama 'Arrow', and the stakes have already been raised. Beyond that, a cross over episode with CW's 'The Flash' is also set to air.

So far, Sara is dead, and her killer remains unidentified, and at large. Nyssa returns to Starling City to deliver Oliver an ultimatum from her father Ra's Al Ghul; he has only 48 hours to find the Sara's murderer or the League of Assassins will start killing the innocent civilians of the city.

The big news for this season is the crossover episode with The Flash titled, "The Brave and the Bold". While tracking down the villain Captain Boomerang (also known by his slightly more menacing moniker, Digger Harkness), Arsenal, Diggle, and Oliver instead have to face off against at A.R.G.U.S. Team.

Arrow and The Flash join in the fray, but not before Harkness can escape to wreck more havoc on the good people of Starling City.

Also at play is the relationship between Nyssa and her father. Ra's Al Ghul is naturally the "Big Bad Guy" of Season 3, but series' executive producer Greg Berlanti stressed the importance of Nyssa to the Ra's Al Ghul character.

"It'd be hard to tell [the Ra's al Ghul] story without telling more of Nyssa's story," he said, so viewers will see more of both in the second half of the season, including just how a young Nyssa developed her skills.

'Arrow' Season 3 Episode 8 entitled "The Brave and the Bold" on Dec. 3 at 8 pm on The CW.