The latest series opener features a deadly gas blast at a Las Vegas complementary medicine spa.
CSI investigators are probing the explosion as the remains of two badly charred women's bodies are brought to the county morgue.
Assistant Chief Medical Examiner Dr David Phillips examines the cadavers which have been burnt beyond all recognition.
'One of these women appears to be a nun,' the CSI unit's materials and element analyst Sara Sidle comments, 'booked in for massage on her whiplash.
'The other is definitely a hooker from the salon's colonic irrigation clinic, all the clues point to her having the spa's flagship detox treatment.
'But which is which is virtually impossible to tell.'
'I can see distinct differences between the two bodies,' Phillips replies, 'one of which has a foamy substance bubbling from her orifice; best guess is that's gonna be our hooker,' Phillips says.
'How can you be so sure, Doc?'
'Well you know that old saying, don't you? A nun has hope in her soul.'