I had unprotected sex and took plan b one step 12 hours later. Here is my question. Can you get pregnant in that 12 hour span? Basically from the time he ejaculated and the time I took the pill, is that possible. Or is that what the pill is for. I just want to know if pregnancy is possible in that 12 hour time.

Plan B isn't 100% effective so yes it is remotely possible. Plan B isn't intended to be a primary means of birth control either so consider using condoms AND the pill to reduce your future chances.