He was very much closer to the pair than I was, and he appeared to be moving in their direction.
At this instant Sir Henry suddenly drew Miss Stapleton to his side.

His arm was round her, but it seemed to me that she was straining away from him with her face averted.

He stooped his head to hers, and she raised one hand as if in protest.

Next moment I saw them spring apart and turn hurriedly round.

Stapleton was the cause of the interruption.