The minute our eyes met, I was seventeen again, my heart racing and my hands trembling. My eyes drifted shut and I was standing in front of my locker, the sounds of the school drifting and floating away as Calvin Klein sucked my entire universe right towards him.

'Mom,' said Marty, and my eyes snapped open again. He was staring at me intently. I was staring right back at him, drinking in every little detail of his face. Over the last thirty years his face as it was then had gradually faded from my mind; when I left my family I wondered what my son looked like now, and racked my brains trying to dredge up his face from 1955. I had been unsuccessful, but now, now I felt like a teenager again with a breathless crush.

After several seconds had passed by Marty stepped forward. 'Mom,' he said again, only now his voice was hard and angry. 'What the hell d'you think you're doing?'

'Oh, Marty…' I whispered, reaching out to steady myself against the doorframe. Tears were beginning to form in my eyes.

'How could you leave Dad?' Marty cried, flinging his arms out on either side of him. 'Are you insane? I went to all that trouble to get you guys back together – and you go blow it. And it makes even less sense now than it would have before, because Dad's not a loser anymore and the house is nice – and you, Mom! You look great! I just don't get it – ' He broke off and looked away, clenching his fists by his sides.

I was barely taking in his words; I could only stare at him. Marty's image was blurring and wavering before me as tears started to spill down my cheeks. 'Look at you, Marty,' I choked out. 'You're all grown up.'

'Jesus,' he muttered. 'When was the last time you saw me?'

I shrugged, hurriedly wiping my eyes with a handkerchief. 'You were about eight. You know as well as I do.'

'No, I don't,' he said impatiently. 'It's just – look, can I come in? This is gonna take a lot of explaining.'

'Of course,' I said hurriedly and held the door open for him, marvelling as he went by how much he had changed.

He followed me down the hall into the kitchen. Glancing back at him, I could see him looking suspiciously at the photographs on the walls. 'Who the hell is he?' he demanded, pointing at a picture of John and me that stood on a small table in the kitchen.

'That's John.'

'Who?'

'John, Marty. You know, my husband.'

'You have a husband?' he shouted. 'What about Dad?'

'Once you've divorced someone, you're not obliged to live like a hermit!' I said indignantly, but a feeling of dread was beginning to creep over me. How could Marty not know about John? Did George, Dave and Linda never say anything about me to Marty? Did they act like I didn't exist?

Marty stood in front of me, glaring, his hands in his pockets. I was astonished again by how he had evolved from a small, cheeky child into a moody, sarky teenager – even though I had seen this side of his before he was even born. Thoughts like these had tormented me while he was growing up – and still did.

'This is like some sort of nightmare, Mom,' he groaned. 'I come back and you guys are divorced and you're married and you hate me – why, Mom? Why d'you hate me? Is it because of what I said to you in 1955?'

It took a moment for the words to sink in; when they did, I literally staggered backwards from their full force. '1955!' I gasped. 'You mean you've gone back? You met me back there?'

'Yeah.' Marty eyed me cautiously. 'And I told you I was your future son. I prob'ly shouldn't have said that…'

'You travelled in time,' I whispered. 'I can't believe it.'

'Yeah, but you know that!' Marty was shouting again. He looked exhausted – his face was pale and dark circles ringed his eyes. 'Jesus, Mom. I told you that thirty years ago. It's gotta have sunk in by now.'

'Thirty years,' I said dazedly. 'It's been thirty years since you saw me? You're only seventeen.' I was barely aware of what I was saying. Was I drunk? Perhaps Marty was a hallucination.

'No. Sheesh. Mom, it's been thirty years for you. But I saw you yesterday, in 1955.'

I blinked and sat down in a kitchen chair. 'That's not possible…'

'Jesus Christ, didn't you ever think about all this stuff, when I told you I was your son from the future?'

'Don't use that sort of language with me,' I said automatically, slipping into the mom-thing again as naturally and easily as breathing. Then I realised what I'd said and clapped my hand over my mouth with a half-sob, half-giggle. 'Oh, my…oh, Marty, you have no idea how strange it feels, saying that. Like you're my son again.'

'But I am your son, Mom,' said Marty tiredly. 'And where I'm from, you've been my mom my whole life – not just part of it.'

I looked at him. 'What?'

He shook his head. 'It doesn't matter. OK, Mom, I need to know where you and Dad went wrong.'

I looked at him blankly.

'Why did you leave Dad? I know it's gotta be because of me, something I did – I mean, it wasn't perfect before, but at least you were still together.'

'We didn't exactly go wrong,' I whispered. 'We loved each other. We were happy. I guess it was you, Marty – George couldn't bear to see the way I treated you. Something came between us, and we knew it was over.' I bit my lip hard, trying to force back the tears that were threatening to spill over. I'd shed enough tears over the years.

Marty was staring at me with an expression akin to shock. 'You split over me?' he said hoarsely. 'Why – how did you treat me?'

'Well, don't you remember when I hit you?'

He closed his eyes. 'No, I don't remember,' he said. His voice was flat and expressionless. 'And I don't really want to know. I just need to know why you treated me like that.'

All of a sudden, the tears were pouring down my cheeks and my face was buried in my hands. 'I'm sorry, Marty,' I whispered, my cheeks wet. 'I'm sorry. I'm sorry. But I loved you so very much, and I couldn't bear to think of what I'd done to you in 1955 – '

'What?' Marty forcefully pulled my hands away from my face. 'What are you talking about? What did you do to me, Mom?'

'Kissed you,' I sniffed miserably.

Unexpectedly, Marty laughed, a short, bitter laugh. 'That's all?'

'What do you mean, that's all?' I was on my feet in an instant, angry all of sudden. I was so furious I was almost shaking. 'Don't you know what it did to me? Don't you know how I've felt over the last thirty years, what I've gone through? I kissed you, Marty. I tried to make out with you. And all I could think of, every time I looked at you, was that I was going to hurt you so badly, maybe traumatise you for life, one day soon. I couldn't live with seeing you so loving towards me. I couldn't stand it.' My voice had grown quieter and quieter as I spoke, and now I sank back into the chair, my knees too weak to support me anymore.

Marty was silent for what seemed a long, long time, then spoke very softly. 'You know what, Mom? I think you were the one who was screwed up by that, not me.'

My face whipped upwards to his. For a moment I forgot how to breathe.

He was nodding. 'Yeah, that's what happened.'

'But…it can't – you…' I suddenly realised something that I'd been slow to catch on to. 'Oh my God! You've been back – so I've kissed you. And yet…you don't care. You don't care.'

'Mom.' Marty sounded unbelievably weary. 'Look at me. Do I look traumatised for life to you? I gotta admit, it was weird when you had the hots for me in 1955, but I know it wasn't your fault. You didn't know. So stop acting like you caused all this to happen. I was the one who caused this. If I hadn't ever told you I was your future son, you would have never – '

He halted abruptly and his eyes grew wide.

'That's it!' he said. 'If I never told you who I was, you would never have felt so guilty and split up with Dad. Jesus, I knew I shouldn't've said anything. I guess it was a bit heavy. Jesus, how the hell am I going to stop myself saying that? Drag me out of the car? God.'

I could sort of see what he was talking about, although I felt dizzy if I thought about it too much. 'The man I met that week, Doctor Brown – will he help you?'

'Shoot me, more like,' Marty muttered. Then, in normal tones, 'Yeah, he'll help me. I have to go now, Mom.'

'No,' I said, catching hold of his sleeve. 'Not yet. Stay a while.'

He pulled away, biting his lip. 'Sorry, Mom. But don't worry, I'll set everything right. I mean – ' he glared, ' – you can't mean to say you're happy with this John guy?'

I swallowed. 'He's a good man,' I said softly. 'He's kind to me. But I'm not happy, no.'

Marty smiled grimly. 'Well, you won't have to worry about that for much longer,' he said. 'Hopefully. See ya, Mom.' He started forward as if to hug me, but then paused, and the moment was lost. We looked at each other for a moment longer; then he turned away and walked out of the kitchen. I heard the front door slam, the truck outside starting up, driving away, the sound becoming fainter and fainter until everything was completely silent again and I wondered if my son's coming had been a dream.