he was already rising , reaching for a bell , and before she knew where she was , a maid-servant had whisked her off upstairs , deftly undressed her , and wrinkling her nose at the smell of the discarded garments , wrapped joan in a robe of the most amazing green silk , light as air , and ushered her into a small stone room with a copper bath in it , then disappeared , saying something in which joan caught the word 'eau ' .