Live 2/5 mystery hand

[feelixthegreek]

Hero got himself into trouble, I feel, by raising the turn. The board is bone dry as far as straights and flushes. Either SB has a monster or air. If Hero feels the need to raise turn, I'm guessing he's weak. But the river overbet makes calling with an TPTK-type hand plausible, because would SB really stop and go with a big hand like 88 or A3 and overbet the pot on the river?