Same thing for me playing co-op. Same area.
We killed the orcs on the beach, and saved upon doing so. We entered the cave, fought the pirate/orc combo, saved, then went down to the Source monster. We weren't ready for him, and tried to reload the last save, which just shut down my game entirely. Tried that a few times without luck, and it kept trying to load for 10 seconds or so, then would shut down. The prior saves didn't work either, so we decided to just call it for the day.
