awkward AK hand

[schwah]

$.5/1 NL

unknown UTG+1 with $80
hero in middle position with $110
SS to hero's left with $13
solid guy on button with $130

PF:
uknown raises to $3
hero calls
SS goes allin for $13
button cold calls
unkown cold calls
hero calls ???????

flop is 9 5 2 rainbow
unknown bets $5 into ~$55 pot
hero ???????