How is my KK overpair line here?

[Karak567]

(first orbit - no reads)

Party Poker No-Limit Hold'em, $ BB (6 max, 5 handed) internettexasholdem.com

BB ($187.79)
UTG ($321.25)
MP ($497.30)
Button ($196.60)
Hero ($221)

Preflop: Hero is SB with K[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/spade.gif[/img]. Hero posts a blind of $1.
UTG calls $2, <font color="#CC3333">MP raises to $7</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero (poster) raises to $24</font>, <font color="#666666">1 fold</font>, UTG folds, MP calls $18.

Flop: ($54) T[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $52</font>, MP calls $52.

Turn: ($158) 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, MP checks.

River: ($158) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero pushes