The Magus

 In John Fowles's novel The Magus, the narrator suspects the other mysterious guests in a mansion on a Greek island are somehow figurants in a masque orchestrated for him by the owner of the house...

 She turned to face the sea again.

'Do you like Maurice?'

'This is only the third time I've met him.' She appeared to wait for me to go on. 'I'm very grateful for his asking me over here. Especially—'

She cut short the compliment. 'We all love him very much.'

'Who is we?'

'His other visitors and myself'. I could hear the inverted commas.

'"Visitor" seems an odd way of putting it.'

'Maurice does not like "ghost".'

I smiled. 'Or "actress"?'

Her face betrayed not the least preparedness to concede, to give up her role.

'We are all actors and actresses, Mr Urfe. You included.'

'Of course. On the stage of the world.'

She smiled and looked down. 'Be patient.'

'I couldn't imagine anyone I'd rather be more patient with. Or credulous about.'

She stared out over the sea. Her voice was suddenly lower, more sincere, out of role.

'Not for me. For Maurice.'

'And for Maurice.'

'You will understand.'

'Is that a promise?'

'A prediction.'

There was a sound from the table. She glanced back, then into my eyes. She had the face I had first seen in the music-room door: both amused and conspiratorial, and now appealing as well.

'Please pretend.'

'Okay. But only in his presence.'

She took my arm and we moved back towards him. He gave us both his little interrogatory headshake. 

'Mr Urfe is very understanding.'

'I am glad.'

'All will be well.'