Episode 18......FUCK YES!!! Blushing dere dere Biri Biri for the massive win win!!!
It's a standalone episode surprisingly, but it did introduce the potential plot point...
Spoiler :
....and that's Touma's so-called faction of befriending the girls from both the magic side and science side will cause future disputes of these overall groups. So this is what the epic battle between science and magic is goin to come?
Episode 19! Well, this is interesting. I believe we got ourselves a new arc that has Accelerator taking up the spotlight. Of course you have to have a moment in order to show that the supposed enemy is actually good deep within! And here's the introduction of a loli MISAKA clone nicknamed Last Order.
Spoiler :
It seems someone implanted a network virus into Last Order. And if it activates, the virus will spread onto the other MISAKAs which will cause them to go berserk.