My girlfriend took plan b.. but after that we had unprotected sex a hour later... is she still safe from becoming pregnant? we only had 1 pill to take

No: Plan b helps to prevent ovulation, however if ovulation has already occurred prior to or just after intercourse, your girlfriend can still get pregnant. I would recommend if you don't want to be a father that you use at least 2 forms of birth control. Most typically condoms for the male and then pills or another method for the female.

Plan B: should be protective for both events.