Both cards' clocks count, so time moves forward by both at the start of the turn.
Then, if an area enchant card is already in set zone C, it's put in the power charger or abyss, and the area enchant card set in set zone A moves to set zone C and has its effect resolved, if it can be used.
The other area enchant card, set in set zone B, doesn't have its effect resolved and is put in the power charger or abyss at the end of the turn.