50NL Zoom on Stars, villain is a UK reg, no reads otherwise. C/r's on monotone flops are usually pretty strong, but I'm not blocking FDs and plus my hand is under-repped so I flat. The turn overbet actually makes me feel that it's more likely he's on a draw, like Ahx maybe. On the river I have $119 left, so I need to be good 39% of the time in order to call here. A real head-scratcher.