TPTK facing 4-flush board

[PennDisc]

These situations are so read dependent - but what do you do facing an unknown? I only played 1 orbit when this hand came up. Villain hadn't played a hand yet, so he's tight, and I have seen nothing of his postflop play.

Party Poker 10/20 Hold'em (10 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Preflop: Hero is UTG with A/images/graemlins/diamond.gif, K/images/graemlins/diamond.gif.
<font color="#CC3333">Hero raises</font>, <font color="#666666">3 folds</font>, <font color="#CC3333">MP2 3-bets</font>, <font color="#666666">5 folds</font>, Hero calls.

Flop: (7.50 SB) A/images/graemlins/heart.gif, 3/images/graemlins/heart.gif, 4/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP2 bets</font>, <font color="#CC3333">Hero raises</font>, MP2 calls.

Turn: (5.75 BB) 7/images/graemlins/heart.gif <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">MP2 raises</font>, Hero ???

I'm not worried about giving free cards anymore after the turn card hits because he's either got the flush or he doesn't, so should I be check-calling from there? Bet-fold? Basically, do I need to get to showdown in a headsup situation like this or can I give up if he gives me indication that I'm beat?

[sy_or_bust]

There's not really a profitable way to reach showdown here, plus the action especially indicates you are behind. To 3-bet an UTG raiser usually takes a medium to high pocket pair, which is 50% likely to hold a heart. Any hand with a king is even more likely. Against an unknown you should fold. He may be bluffing, but you're out of position and this is a very costly call down, plus sometimes you'll catch a bluff and lose or split.

[mdeck]

I think if Villain is tight he wouldn't bluff at this. 10/20 is above me, but I'm pretty sure that I'd bet/fold this turn. More often than not a tight villain wouldn't bluff raise with 4 to a flush on the board.

[aba20]

Against an unkown I check call down. Against a tricky tough opponent I check call down. Against a loose passive fish I bet fold to a raise.

[Klepton]

MP would have folded the flop after your checkraise if he didn't have a heart.

everyone is capable of making moves, but you already committed yourself to the bet/fold plan.

if you can't bet/fold, then check/call. this isn't about giving him a free card as it's already a slightly ahead/ extremely behind senario.