twelve o'clock
`` Silence -- silence , I implore you ! '' continued she , in the rapid , low , and yet distinctly audible whisper , `` for _ your _ sake -- for _ mine _ , betray me not ! Deaf and dumb must I appear -- deaf and dumb must I yet be deemed for a short space . But to-night , at twelve o'clock , you will meet me , Demetrius , in the garden of the Riverola mansion ; -- and then I will conduct you to an apartment where we may confer without fear of being overheard -- without danger of interruption . '' `` I will not fail thee , lady , '' said the Greek , scarcely able to recover from the amazement into which Nisida 's sudden revelation of her power of speech and hearing had thrown him : then , as an oppressive feeling seized upon his soul , he demanded , `` But Calanthe , lady , in the name of heaven ! one word more and let that word give me hope that I may see my sister again ! '' `` Demetrius , '' answered Nisida , her countenance becoming ominous and somber , `` you will never behold her more .