When plays are rarely performed you do wonder if there is a good reason for it and Cymberline isn't one of William Shakespeare's best but the RSC has done a superb job with it, particularly given that they do the whole thing.
It's definitely a play of two halves. As we paused for the interval it was all going swimmingly. Queen Cymberline (Gillian Bevan), one of several gender swaps in this production, is angry that her only daughter Innogen (Bethan Cullinan) has married her lover Posthumus (Hiran Abeysekera) and has banished him but not before the newly-weds swap gifts - a ring for Posthumus and bracelet for Innogen. Innogen's evil stepfather (James Clyde) wants Innogen to marry his oafish son Cloten (Marcus Griffiths) but he also has deadly plans for the Queen.
Things take a turn for the worse for Posthumus who, having made his way to Rome, encounters Iachimo (Oliver Johnstone), a playboy, who in hearing about the lovely and chaste Innogen wagers that he can prove she isn't by tempting her to bed. Posthumus bets the ring that Innogen has given him and you can see roughly where all that is going. Anyway that brings us up to the interval with a lot of people feeling rejected/hurt/bereft while others are rubbing their hands together in glee.