pocKK, and villian donks when Ace on flop

[maverickai]

No reads on villian

PokerStars 0.05/0.10 Hold'em (10 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is MP2 with K[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img].
<font color="#666666">3 folds</font>, <font color="#CC3333">MP1 raises</font>, <font color="#CC3333">HERO 3-bets</font>, <font color="#666666">5 folds</font>, MP1 calls.

Flop: (7.40 SB) 9[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP1 bets</font>, <font color="#CC3333">HERO ??

How to analyse this kinda situation when villian donks with an ace, and I have no reads on him?

I always have difficulty knowing what to do in this kinda situation.