Smoke from spark plug hole

I drove the car to somewhere and ran fine. Left it over night at mates whilst it rained. I drove back home noticing the car wasnt running right, it was stuttering. I tried to turn the engine on today to see if it's still not running quite right (this is with choke fully out) and the engine seemed to crank over then die out. Took the spark plugs out which were a bit black and the number 2 spark plug hole had smoke coming out of it. The battery is fine. I dunno what it is