On the sixteenth day, Mav did not hunt, and he did not build.
He lay on his stomach behind the wall, with his chin on a flat stone, and watched the eel from the last light of one day to the first light of the next.
He had decided that he would not make another plan until he knew what he was planning against.
He had attacked the crab without knowing anything about it.
That had cost him a harpoon and almost a leg.
He had gone into the deep water without knowing what lived there.
That had cost him Three and Four.
‘I do not get a third mistake.
So tonight, I only look.’
He kept a list in his head, and he added to it all night.
The first thing he learned was when the eel came.
During the day, it stayed away.
He could feel it sometimes, far down the slope, as a faint unease in his seaweeds.
But it only came up to the base when the light from the surface began to fail.
It arrived at dusk, circled all night, and left at dawn.
‘It hunts in the dark.
It has no eyes, so the dark costs it nothing.
Everything else is blind at night, and the eel is not.
It has amazing sensory skills.’
The second thing was its size.
When it passed in front of a boulder he had measured with the harpoon, he could finally be sure.
It was a little over four meters long, and as thick as his thigh.
The third thing was the light.
The eel never crossed into the green glow.
Not once in six nights.
It would come right up to the edge of the glow and slide along it, as if the light were a wall.
Mav did not understand why.
The eel was blind.
Light should have meant nothing to it.
He thought about it for a long time and found only one answer that made sense.
It was not the light that the eel avoided.
It was whatever made the light.
The glow came from his seaweeds and from the Heartstone, and a creature that could sense a small fish in black water could surely sense those.
‘It does not come close to the Heartstone.
I cannot be sure that it never will.
I should not build a plan on that.’
The fourth thing took most of the night.
A large silver fish, bigger than a needlefish, came up the slope after dark.
It was lost, or sick.
It swam in a wavering line, straight past the eel.
The eel turned.
There was the flash.
Even behind his wall, 30 meters away, Mav felt it prickle across his skin.
The silver fish went stiff.
The eel swallowed it whole, without hurry.
He had seen that before, and it had cost him two Subjects.
This time, he was not looking at the prey.
He was counting.
A minute later, a second fish blundered past.
It was closer to the eel than the first had been.
The eel did not flash.
It lunged and missed, and the fish fled into the dark.
Mav kept counting.
He counted slowly and steadily.
A third fish came by when he had reached 80, and the eel only chased it.
He reached 90.
Then 100.
At 110, a fish swam too close, and the sea turned white again.
‘It cannot do it twice in a row.
It needs time between two flashes.
More than a minute and a half.
Also, I’m sure that these flashes are an electric skill.’
He watched until dawn to be sure.
He saw it flash three more times that night, and each time, he counted.
The shortest gap was 104.
It was never less.
That was the most valuable thing he had learned since he arrived, and Mav felt his excitement grow.
He learned two more before the eel left.
The flash had a reach.
Fish that were within four or five meters of the eel went stiff and died.
Fish further away only jerked and fled.
On the tenth day, at 20 meters, the flash had hurt him.
It had not stopped him.
And the eel was long.
That was its strength in open water.
Among rocks, it was a weakness.
Near dawn, it pushed its head into a gap between two boulders after a shrimp, and when it wanted to leave, it could not turn around.
It had to back out, slowly, a little at a time, the whole length of its body.
Mav watched it do that, and felt something go still inside him.
When the light came back, he sat by the Heartstone and went through his list.
The eel hunted at night.
It was four meters long and as thick as his thigh.
Its flash killed within five meters.
After a flash, it needed more than 100 seconds before it could flash again.
In a narrow place, it could not turn.
It could only go forward, or back out slowly.
And it always went for the largest prey in reach.
It had ignored the shrimp for the silver fish.
On the eleventh day, it had ignored Six and the two fish, and had come straight for him.
He turned that over for a while.
He could not kill it.
Nothing he owned could wound it in open water.
Two was rank F, and the eel had been born two steps above that.
In a fair fight, it would swallow every Subject he had.
‘So there is no fight.
It is stronger than everything I have.
I do not beat it.
I trap it.’
He needed three things.
He needed a place where the eel could go in and could not turn around.
He needed something strong enough to hurt it while it was stuck.
Six had already hit its jaw once.
And he needed something to make it go into that place, of its own will, as deep as it could go.
The first two were work.
He could do work.
The third was the one that had nearly killed him five days ago, when he had tried to pay for it with Five.
Mav looked at his 10 Subjects.
Two and Five drifted near the gate.
Six stood by the larder.
The four old seaweeds swayed in their cracks, and beside them, Eleven and Twelve glowed like two small candles.
He was not going to send any of them.
He had given his word.
And the eel had already told him what it wanted most.
It wanted the largest thing in the water.
The thought made his stomach turn.
Mav already knew what the bait would be.