Nothing that was a great surprise. Helen (the widowed twin) was quite obviously trying to "take over" Carol's life. Carol sussed her and talked to Douglas (the doc) about it. He did some background work and discovered that Helen had a "colourful" past. Just in the nick of time he found out that she had a history of burning down houses. He rushed to the house and found it on fire (surprise, surprise). Only one of the twins survived and dental records confirmed that it was Carol...but earlier in the episode Helen had been to the dentist - Carol's dentist. It was clear that somehow Helen had switched the records (this was never explained, and seems highly implausible however...) The doc accused her and she virtually admitted to being Helen. The husband appeared to realise, but we were left with the impression that he was prepared to accept the situation. Obviously there was much psychobabble padding, and drama involved, but that is the main points. Hope this is helpful. Anyone who wants to contribute further please feel free - I won't feel slighted in any way! Not great but better than reality TV any day!