"What you don't do is touch those contacts. Or you'll fry. What we do now is, we test it." He picked up the slave switch and pulled the trigger. Ellen heard two beeps from somewhere deep in the hull of the boat. Jake stared at the strobe, as if trying to hypnotize it.

"Sonic transmitter's working, anyway," said Mike.

"What the hell good's that?" Jake said, flaring. He glared at Mike. "I told you to keep this thing charged!"

"Somebody turned off the battery power," Mike said simply. "It happens."

Boom, boom, boom, boom...

Again the shark struck forward. The bow rose, shivered, and crashed down. Ellen found herself slammed between the chart table and the galley, on the deck.

Jake and Mike picked themselves up. Mike pulled the trigger again. Ellen heard two beeps from below. At the second beep the pilothouse was lit with a flash so strong that for a moment she could not see.

Over the boom... boom... boom of the heartbeat they heard a feeble whine. It grew louder and higher in tone, like a tiny scream, until the pitch was so high that it disappeared.

"It's recharging!" exulted Jake.

Ellen suddenly understood. The flash unit on her own camera did that when she took pictures of Thea. "But how are you going to get it on him?"

Jake grinned. "Not on him. In him. With a boat hook."

She stared at him. "From where?"

"The bowsprit. What's left of it. The next time he opens his mouth."

Mike tensed. "That's my job."

Jake looked into his eyes. "No."

"Come on, man. You're too big for tightrope walking. There's no forestay to hang on to. You don't have the balance."

"Better balance than you, harpooner. You almost fell in."

"Well, I speared him, didn't I?"

"So it's my turn now," Jake insisted.

Yes, let him, let him do it! Ellen begged silently. She squeezed Mike's hand. He looked into her eyes.

Whatever he read there, he understood. He sighed and nodded. "Okay."

***

Louisa was washing Jake's socks in their bathroom sink. It was strange; when she had moved in with him, she found that he wore his socks for a week at a time, then threw them away and bought new ones.

Now, although he wouldn't dream of washing them himself, he seemed to change them twice a day.

She wondered where he was. He had taken off like a scalded cat from the shark attack on the beach, heading for Mike's. He seemed to blame himself, as if the shark were his fault and he somehow thought he could hunt it down with the boat.

He was probably looking for it now.

She looked at the socks. One had a hole. Her mother I would have darned it. She didn't even know how. She threw it in the trash and couldn't find its mate.

If one of a pair was gone, what good was the other one?