When an angry Rosa tells Nathan that he's given her an STD, he foresees a whole world of trouble - if he's given it to Fi, she could have given it to Jase, and then Jase will know that his best mate's been shagging his girlfriend. Added to Nathan's troubles is his latest assignment from Peggy: a hands-on, no-holds-barred account of the Swinging scene - no spectating allowed. Nathan's not exactly 'match fit', but when he confides in his male-to-female transsexual colleague Fay, she tells him that it's Fi he should be worried about... But it looks like Fi is already infected... which means it's only a matter of time until Jase finds out the truth - and then 'To Swing or Not To Swing' will be the least of Nathan's problems... (thetvdb.com)