Both villains are unknown - less than ten hands on both when this hand occurs. What's our plan on the turn?

Full Tilt No-Limit Hold'em, $1.00 BB (8 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

BB ($98.50)
UTG ($150.80)
UTG+1 ($105.30)
MP1 ($22.05)
Hero (MP2) ($100)
CO ($18.50)
Button ($96)
SB ($103.95)

Preflop: Hero is MP2 with ,
1 fold, UTG+1 calls $1, 1 fold, Hero calls $1, 1 fold, Button bets $5.50, 2 folds, UTG+1 calls $4.50, Hero calls $4.50

Flop: ($18) , , (3 players)
UTG+1 checks, Hero bets $14, Button calls $14, UTG+1 calls $14

Turn: ($60) (3 players)
UTG+1 checks, Hero?

I bet..... $38.5, stack sizes are a bit awkward here.

I'm going to shut down, and c/c a reasonable bet from the button. Button could've flopped a set or made one on the turn, and AK is likely too, I'm not too worried he has a flush but UTG's c/c on the flop screams draw or set of 8's.

I'm not going anywhere with this hand, so we might as well get it in now.

Ah yes, the ol' "I haz a set omg i can't fold" school of thought. I would advocate your line if I subscribed to that school of thought too.

Full Tilt No-Limit Hold'em, $1.00 BB (8 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

BB ($98.50)
UTG ($150.80)
UTG+1 ($105.30)
MP1 ($22.05)
Hero (MP2) ($100)
CO ($18.50)
Button ($96)
SB ($103.95)

Preflop: Hero is MP2 with ,
1 fold, UTG+1 calls $1, 1 fold, Hero calls $1, 1 fold, Button bets $5.50, 2 folds, UTG+1 calls $4.50, Hero calls $4.50

Flop: ($18) , , (3 players)
UTG+1 checks, Hero bets $14, Button calls $14, UTG+1 calls $14

Turn: ($60) (3 players)
UTG+1 checks, Hero checks, Button bets $26, UTG+1 folds, Hero calls

River: ($112) (2 players)
Hero?

So I c/c the button's bet like Donk's line and I boat up on the river. Do we bet or check/call assuming button bets his remaining $50?

Shove river AINEC. You can't let him check behind, and you were never going to fold.

shove river, he isn't folding

Here was my thought process; if I check, he's betting any boat, flush, AK, any K and he might bluff with air. If I bet, he's calling with boat, AK, flush any K and folds everything else (couldn't really see him having an ace there since the Ac hit the board).

So I checked and he shoved with two red nines.

I was thinking he might check behind with an Ace but would probably call a bet.

I just couldn't see an ace besides AK/AA. If he had Ax - he wouldn't have the FD so what other ace calls the flop that raised pre on the button?

I know it doesn't make sense for him to show with another Ace but that doesn't mean I don't expect it some % of the time. I mean it doesn't really make sense for him to shove the river with 99 either.

Yeah, that's true. 99 wasn't exactly in the range I had for him.

Results oriented thinking, IMO. This is a board no sane villain will be bluffing the river at when you are so committed. This, along with other more reasonable holdings, are the kind of hands that villain will be checking behind with but might call the river bet.

Never underestimate how often villains show up with strange Ace-x's. Also, no guarantee he would bet a small flush with the board pairing. You're over-complicating this.

I haz a set omg i can't fold.

Not sure why you're saying that here, Base. At what point should the OP have folded his hand? Certainly not on the river...and you're not advocating a c/f on the turn, are you?

No, I don't think he should fold at all.

I'm just borrowing DonkSlayer's language for the opposite opinion.

I don't fold sets much, and I'd think it would have to be an extremely tight game to make folding a good idea.

Who in their right mind folds a set on the turn? LOL. ZOMG A FLUSH HIT THE BOARD I FOLD ... LOL

You guys are just yacking right??? I never said fold the turn before the action unfolded.

But yeah, given the action, if the turn action went exactly check check button big bet SB RRAI, I'm folding.