midnight

Thanks to its sonar, the narwhal can remain active even at midnight, unhindered by the darkness.

She twisted her hands behind her; but all the knots held good! / She writhed her hands till her fingers were wet with sweat or blood! / They stretched and strained in the darkness, and the hours crawled by like years, / Till, now, on the stroke of midnight, / Cold, on the stroke of midnight, / The tip of one finger touched it! The trigger at least was hers!