"You have the secret.

It's good Triad writing.
Subtract this twisted character 'Lightning' from each, and we've made the crooked straight.

The writer was afraid of being caught.

Here's the sense of his message, I take it." And he read off, slowly:-- "A Hakka boat on opposite shore; a green flag and a rice-scoop hoisted at her mast; light a fire on the water-gate steps, and she will come quickly, day or night .-- O.W." Heywood took the news coldly.

He shook his head, and stood thinking.
"That won't help," he said curtly.