Rivering a set but should I fold?

[twolf]

Party Poker No-Limit Hold'em, $0.50 BB (10 handed)

UTG+2 ($39.20)
MP1 ($24.50)
MP2 ($25)
MP3 ($25.77)
CO ($72.25)
Button ($18.50)
SB ($24)
Hero ($25)
UTG ($35.55)
UTG+1 ($19.20)

Preflop: Hero is BB with 6[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/diamond.gif[/img].
UTG folds, UTG+1 folds, UTG+2 folds, MP1 folds, MP2 folds, MP3 folds, CO folds, Button calls $0.50, SB completes, Hero checks.

Flop: ($1.50) K[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/diamond.gif[/img] <font color="blue">(3 players) </font>
SB checks, Hero checks, Button checks.

Turn: ($1.50) 7[img]/images/graemlins/club.gif[/img] <font color="blue">(3 players) </font>
SB checks, Hero checks, Button checks.

River: ($1.50) 6[img]/images/graemlins/club.gif[/img] <font color="blue">(3 players) </font>
SB bets $1, Hero raises to $5, Button folds, SB raises to $23.5 (All-In), Hero....???

This was my very first hand at the table though I did watch a few hands and saw the SB go all in on the river on a busted straight draw once and got called by KK. Would anybody else raise this river bet?

[cornell2005]

raising is good and i think folding is good too.

theres 2 options, either he is the type that thinks "hmm why would he raise me? i dont trust him, so ill push" or he has you beat. no hand that you can beat is a plausible holding here, he would have played it differently with all other hands except maybe 77.

the fact that hes in the SB makes a long slowplay more possible, but still strange. overall id fold also, but its hard to tell here because no matter what he is holding he made mistakes. hard to see which were intentional and which were not.

[twolf]

Very big mistake for him, he had 9 [img]/images/graemlins/diamond.gif[/img]T [img]/images/graemlins/diamond.gif[/img] for the flopped str8 flush. Thanks for the advice.