You need to take all people to the other side of the river using a raft. However, there are limitations:
Only adults (with an obvious exception of the prisoner) can steer the raft:
You cannot leave anyone with the prisoner unless the policeman stays by:
The prisoner may be left on its own, though.
Girls are afraid of the stranger man and can't be left with him unless their mother is close by. Similairly, boys can't be left in presence of the woman without their father.
The kids may be left with each other, alone on the shore and they trust the policeman.