PokerStars No-Limit Hold'em, $0.10 BB (9 handed) from (Format: FlopTurnRiver)

CO ($5.90)
Button ($13.15)
SB ($2.15)
BB ($7.85)
UTG ($2.65)
Hero ($24.75)
MP1 ($7.40)
MP2 ($8.55)
MP3 ($24.40)

Preflop: Hero is UTG+1 with J, J. CO posts a blind of $0.10.
1 fold, Hero raises to $0.4, 2 folds, MP3 raises to $1, 1 fold, Button calls $1, 1 fold, BB calls $0.90, Hero calls $0.60.

Flop: ($4.15) 4, K, J (4 players)
BB checks, Hero bets $0.5, MP3 raises to $3, Button folds, BB folds, Hero raises to $8, MP3 raises to $23.4, Hero calls $15.40.

Turn: ($50.95) 8 (2 players)

River: ($50.95) 2 (2 players)

Final Pot: $50.95

Results in white below:
Hero has Jh Js (three of a kind, jacks).
MP3 has Kc Kh (three of a kind, kings).
Outcome: MP3 wins $50.95.

Now THAT is truelly unlucky.. set over setted with 250BBs Virtually impossible to get away from your hand of course, especially at this level where he could easily have AA/AK.

One thing though, your small bet on the flop doesn't really serve a good purpose - either check or make a real bet ($3 - $4)