Heavy woollen robes dragged round my ankles, and I felt uneasy and misplaced. The Underworld was grey to me, even in the Isle of the Blessed, the brightest of the afterlives. Immortals did not fit in this place of the dead. None but Hades, who was in his element, so to speak, and seemed to take a perverse pleasure in the discomfort of the rest of us. I could see, as though through a veil, the beautiful mountains and fields of Elysia, but it had none of the glittering splendour of Olympus or even the simple sweetness of mortal Earth.

"Grand-daughter." The voice was hoarse and cracked with disuse, and came from behind me. I turned and carefully hid my disgust and pity as I gazed on the bent, feeble remnants of the once-ruler of the Titans.

"Chronos." I infused my tone with precise amounts of affection and respect, neither of which the fallen deity inspired. It was hard to believe, looking at the wrecked shell in front of me, that this had once waged war on the Olympian gods. Tartarus weakened him, I thought, but Zeus truly broke him when he dredged him up from the pit and made him subservient. The former king was now a 'pet' of his conquerors, allowed to watch over Isle of the Blessed by the grace of the children he had scorned. "I have come to ask something of you."

The old Titan wasted no words; conversation seemed to fatigue him and I wondered if he even had the strength to assist me. "What?"

"I need you to send me back in time," I told him simply. "To 2005. I need to change the past, to better the present."

"To meddle, you mean." His growl would have been intimidating, had he not fallen to coughing weakly immediately afterwards. He regained his breath and continued speaking. "In the affairs of mortals?"

"You assume correctly." I was neutral. His disapproval meant nothing to me.

"Humm." He coughed. "We took no part in their foolishness, when we ruled."

I refrained from commenting, wise enough to see that any reminder of his fall from grace would enrage him. He waited a moment, then snorted with hacking laughter. "Well, it's not like I'm in any position to refuse you, is it, Olympian?"

I could hear easily the bitter, undisguised hatred he wrapped around the word, but tamped down the emotion it stirred in me and locked my coldest grey stare on the Titan. "If you will help, you must help now."

His fragile body gradually stopped shaking. "You cannot contact any other gods, titans, lesser deities, demigods, any who may know you. You cannot allow any to know who you are, or that you have come from their future. To this end, you must use your godly powers sparingly."

I nodded elegantly. "All this I know."

"I shall endow you with enough of my own power to anchor you in that past for thirteen days. Then, your natural pull to your own time will reassert itself, and you shall be returned here."

I felt my brow crinkle as my eyebrows slanted. "Thirteen days will not be enough."

Chronos jeered, delighting in whatever petty inconvenience he could cause. "I cannot give you any more. Only thirteen days!"

He suddenly peered intently up at me from his stooped position, curiosity lighting deep in the cobwebbed depths of his rheumy eyes. "What is it you intend to do?"

I ignored the question, my brain whirring to solve the puzzle, as it always did. I flipped lightning-fast through possible solutions, discarding one after another until one showed promise. I met the eyes of the Father of Time.

"Can you give me thirteen days of my choosing? Thirteen disparate days of the past for me to 'meddle' in?"

He hunched lower into himself, his lips mumbling without sound. His spidery fingers flexed and clawed. "Maybe, maybe, Athene. You must choose your first day, the first day now. Then, when that sun sets, choose the next. Then the next and the next, for twelve sunsets. Do you understand?"

Of course I did. I plucked from my memory the first day I had to alter. "The 25th of December, 2004."

He shut his papery eyelids and stood immobile. His head snapped to the side, as if following a sound, and he seemed to watch something with his eyes closed. "I see it." He said softly. "Thirteen days, Athene. Trust me." He started to cackle. "You'll be back before you're gone!"

I sensed the sharp tug as he drew on his power, and I was caught in a hurricane I couldn't see or physically feel. The world seemed to stagger and almost fall around me, before righting itself. In the brief instant when everything was tilted, a figure stepped into my peripheral vision and then

I was standing exactly where I had been before, but Chronos was nowhere to be seen. I had successfully travelled through time and had returned to 2005, but I was instantly faced with a problem I would have foreseen, had I had more knowledge of the process of time travel. I now knew that I had moved temporally, but not physically and was still standing in Hades' realm. But it was years before I would ask his permission to enter, and I was supposed to avoid contact with other gods. I inhaled slowly, cringing at the dusty, stale scent of the Underworld and brushed my hair out of my eyes. Look at it like a puzzle, I told myself. The objective is to leave the Underworld without alerting Hades to your presence. The obstacles are the Underworld's defences, primarily Cerberus and Charon. My mind spun, weaving plans and answers and catching flaws and knots, until the pattern I needed revealed itself to me.