She thought she recognised the figure of Lady Arabella, and instinctively drew back behind the curtain.

When she had ascertained, by peeping out several times, that the lady had not seen her, she watched more carefully, all her instinctive hatred flooding back at the sight of her.

Lady Arabella was moving swiftly and stealthily, looking back and around her at intervals, as if she feared to be followed.

This gave Mimi an idea that she was up to no good, so she determined to seize the occasion for watching her in more detail.
Hastily putting on a dark cloak and hat, she ran downstairs and out into the avenue.

Lady Arabella had moved, but the sheen of her white dress was still to be seen among the young oaks around the gateway.