Climbing down from Jaime's bedroom window hadn't been difficult. He had long ago identified all the notches and handholds on the castle wall outside his room and carved them out where necessary, so in less than five minutes they were on the ground. What was more difficult was figuring out how to get a horse now that the grooms and stablehands had no doubt been told not to let her in.

Jaime left her hiding behind the old Well and went swaggering up to the stable as if he were Lord of the Rock already. Cersei didn't really expect that he'd be allowed to take a horse out without the grooms at least checking with Father first, but Jaime must have spun them a good line of bluster because he came riding out on Father's own white stallion. Damn boys, they really do have it easy in life, she thought.

The stallion was so tall and wide across that Jaime's skinny legs didn't reach to the bottom of the girth, and he perched on its back as if a strong gust of wind would unseat him. The look on his face was so smug that Cersei almost wanted to push him off herself. But then they wouldn't be going anywhere, so instead she stood on tiptoe on the low wall of the Well and swung her leg over the stallion's back as he rode up alongside. 'How did you talk them into letting you take Father's horse?' she wanted to know, wrapping her arms around his waist.

'I told them he'd asked me to excersize it for him.'

'And they believed you?'

'Well he wasn't around to say no. He's down on the beach, with the Captain of the Guard, talking about putting in another catapult. Or something.'

'You'll be in trouble if he finds out.'

Jaime let go of the reins and spread his hands wide. 'The things I do for my sister.' He kicked the stallion abruptly into a gallop with his hands still outstretched, and Cersei squealed as the horse accelerated with unexpected speed. It was Father's best war-horse, after all. The sea breeze blew hard in their faces, the horse's powerful strides flew down the slope, and her squeals turned to laughter. Doing forbidden things with Jaime? There is nothing better in the world, she thought.

They reached the rock pool while the sun still had enough warmth to make the blue water look like a gift from the gods, made just for them. Jaime let out a whoop on seeing it, and took off charging for the waterfall before the horse had even fully stopped, shedding clothes as he went. It was left to Cersei to get the stallion under control and tie it securely to a tree, and she turned around just in time to see her brother standing on the highest point of the rocks, waiting for her attention.

His naked skin glowed bronze in the slanting rays of sun. He looked so small up there her breath caught in her throat, but he dived off and out in a confident arc and easily cleared the waterfall. He surfaced beside the cascading spray, flicked his hair from his face, dived under again and swam beneath the water all the way to the bank. Cersei could see right to the bottom of the pool, it was so clear. Jaime looked like a seal undulating through the water, all sleek and graceful.

She stood on the bank above where he re-surfaced, and grinned down at him. She knew he'd love this place, and she was never wrong about Jaime.

'You're right. This is amazing,' he said. 'Get in here.'

She stripped off the clothes he'd given her to wear in place of her ripped gown; they were his clothes but fit her well. They were both similar build with long legs and narrow hips. She took a running jump off the bank and cleared him, swung her arms over her head and hands together, cut into the water in a perfect knife shape.

The water was cold as she plunged down into the depths. At the bottom she cruised along the pebbly floor, admiring the dapples of sunlight patterning her arms in wavy diagonals, drifting in the gentle swell of the current. Then Jaime grabbed her from behind and flipped her over. She kicked and freed herself, heading for the surface in a stream of bubbles. He let her take a breath before dragging her back under again by the ankles.

She managed to wriggle free and swam to the rocks, climbing out of the water before he could reach her. She screamed and splashed him in the face, then she leapt across the slippery stones till she reached a wide, flat boulder. The late sun bounced off the shiny surface and cast a rainbow through the mist rising off the waterfall.

Cersei sat down and waited for Jaime to catch up. He bent and shook his hair all over her, and she splashed him again. Then they lay on their stomachs on the warm rock side by side and let the sun slowly dry their wet bodies.

In the reflection below, as they leaned their head and arms over the edge, they looked like replicas of each other. Her long hair and his broader shoulders the only discernible differences. It pleased Cersei to look at their symmetrical faces, the beauty of them evident even in the shimmering water.

'Let's come here every day,' Jaime said.

'I think Father will have something to say about that,' she countered.

'We'll find a way,' Jaime said. 'What he doesn't know won't hurt him.'

'I think we'll be the ones getting hurt.'

'But it will be worth it.' He stretched out, trailed a hand down her back. It tickled. 'Maybe we can bring Tyrry.'

Cersei pulled a face. 'He's barely off his wet nurse. He can't swim.' And I don't want anyone else here, ruining our special place. Especially not him.

'He can swim, a bit. I've been teaching him.'

'What? When?'

'During the day. On the beach. While you've been... doing your lessons.'

She frowned. She knew her brothers had grown closer this last year, by circumstance, because she was so often kept inside doing pointless and boring craft. But teaching the little monster to swim? It infuriated her that she'd been replaced in Jaime's day-to-day life by someone who never should even have existed. It should be her and Jaime doing things together; it should be her and Jaime and no-one else.

She rolled away from him and crawled to another rock where he couldn't reach her. Put her legs in the water and pretended to be absorbed in their smooth perfection, watching the droplets glisten along her creamy skin as she moved her feet under the surface. Jaime came up behind her and she jumped into the pool, keeping out of his reach. He jumped in after her, and she duck-dived away, swimming fast to the bank.

She put her hands on the edge and went to lift herself out, but Jaime caught her and spun her round. She pushed at him, and he grabbed her wrists and held fast. For maybe the first time, although she'd suspected it for a while, she was aware of how he was now stronger than her.

Because he spends all day outside fighting, while I spend all day sewing, she thought. Fighting and playing and swimming with Tyrion. That ugly, useless, interfering little imp.

'Let me go,' she hissed. She struggled to free her hands.

Jaime pressed right up against her with the whole length of his body so she was pinned to the bank. In the cold water, his skin felt hot. 'What's wrong?' he said. 'Don't be mad at me, Cers.'

'I'm sorry I brought you here. I won't come here again with you. You can bring Tyrion here instead.' She spat out the name as if it were a curse.

Jaime looked confused, and upset. 'I don't want to come here without you.'

She looked away, her jaw set.

Jaime didn't let her hands go, but leaned in to breathe in her hair. He rested his forehead lightly on hers. 'I only want to come here with you. I miss you.'

'I miss you too,' she whispered, letting her body go limp. 'I don't like hearing about you and Tyrion... doing things together.'

'I promise, I won't talk to Tyrion for the rest of the week. Not a word.' He put his hand on his heart. 'If he looks at me, I'll spit on his feet.'

She giggled.

'If he talks to me, I'll fart in his face.'

Cersei laughed, and Jaime's eyes lit up like the sound of it was all he wanted to hear for the rest of his life. He crossed his eyes and poked out his tongue. She poked out hers back, and leaning forward suddenly, licked his cheek. He grimaced and exclaimed in surprise, let her hands go to wipe it. In a flash she'd escaped him and was up on the bank, skipping back to where she'd left the clothes. He let her go with a grin and rested his arms on the bank.

'You win,' he called after her.

She turned around with the clothes in one hand, gave a little teasing shimmy to goad him now that he was too far away to catch her. She did a victory dance, pirouetted in a circle.

When she looked back at him, he wasn't grinning any more. He was staring at her in a strange way, his expression serious and his eyes darker than she'd ever seen them. It was disconcerting, and she held the clothes in front of her. The sun was going down, and her skin prickled with goosebumps all over.

'Come on, we better get back before they miss us,' she said.

Jaime stared at her thoughtfully a moment longer, then backflipped lazily into the water and swam away.