KK meets so-so board meets weird play

[Harv72b]

Haven't posted a hand in a while. I thought this one made for an interesting river decision.

Reads: MP3 is a so-so sLAG over ~50 hands (29/15/1.5). BB is a 2+2'er who's seeing the flop for pot odds. The Button is 23/3/1.5 over about 240 hands; he shows the most aggression on the turn, where he's got a respectable 2.11 AF. He has not struck me as being at all tricky thus far, and if anything has seemed like a subpar (but decent) player.

My own image is a little blotty; I've lost to a few river cards and made a couple of questionable A-high calldowns.

Party Poker 5/10 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: Hero is UTG with K[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises</font>, <font color="#666666">3 folds</font>, MP3 calls, <font color="#666666">1 fold</font>, Button calls, <font color="#666666">1 fold</font>, BB calls.

Flop: (8.40 SB) A[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, <font color="#CC3333">Hero bets</font>, MP3 folds, Button calls, BB folds.

Turn: (5.20 BB) 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, Button calls.

River: (7.20 BB) T[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero...?

What's the plan?