Yes, he was tired - that was hardly surprising.
He was 70 years old and, since suddenly becoming the family's sole breadwinner, he'd kept his small shop open much longer in the forlorn hope that 16-hour days could bridge the gap between what he usually earned and what they needed to survive.
However, despite his efforts, he wasn't too tired to be certain he'd been nowhere near a bank for almost a week.
As he pondered this mystery, his grandson, Ethan Tai Sui-man, sat snoring gently in an otherwise empty classroom in St Jude's International School.
Sam just got his hand out as his locker slammed shut. "What the ..."
Leaning against the door, Maya looked decidedly unrepentant. "What's going on with Ethan?"
"Well, since his mum's in intensive care, I guess he's probably a little worried."
"A little worried? He's so exhausted he's going to end up in the hospital bed beside her. And I assume you've noticed the ..." she trailed off.
Sam finished her sentence: "Smell? I think everyone in school, and half the flies in Hong Kong, have noticed that."
Maya shook her head in disgust.
"He's falling apart and his best friend can't even be bothered to talk to him."
As she turned away, a furious Sam grabbed her arm. "It's not I can't be bothered, it's he doesn't want to talk. And have you tried? He likes you, you know. I assume YOU'VE noticed that."
For once, Maya looked chastened. "Yeah, I've tried, but ..."
She broke off as, simultaneously, her and Sam's phones beeped. One glance at the photo that appeared on both their screens sent them racing down the corridor.
"I was going to wake him up on my way out," Ethan heard Sam say, as he slowly opened his eyes to see his pal and Maya - of all people! - staring at him wide-eyed.
As he shot upright, something slid down over his right eye.
"Only in their IQ-free universe, could tweedle dum and tweedle dumber think this was funny," Maya said. She shook her head at the sight of Ethan still sitting as in the photo the Chan twins had staged -and posted on the net - while he slept.
Looking down, Ethan now saw a scrubbing brush had been placed in one of his hands and a bottle of disinfectant in the other. Dropping these, Ethan snatched a large and frilly shower cap from his head.
The pitying look on Maya's face only made his anger - and his soul-crushing embarrassment - all the greater. Leaping to his feet, he hurled the cap across the room.
As Ethan burst out of the main doors of the school, his face was like thunder.
"I talked to my parents," Sam said, struggling to keep up. "You could stay at our place. We could hang out, do our homework, and you ... you could do the coding for your website ..."
"You think I've got time for any of that?" Ethan snapped.
"But ... I thought they only let you visit your Mum for an hour."
As he shoved open the gate, Ethan looked at him with something like fear in his eyes. "Leave me alone, Sam. Ok?"
It had taken a huge effort to get out before Grandad returned from the shop, and now, as he hurried through the darkened streets, Ethan had the sense he was being followed. While he knew weariness could play tricks with the mind, he also knew that Wai-hung, the leader of the gang on his estate, took disappointment badly. And Ethan had disappointed him.
Picking up speed as he crossed the road, he darted down an alley, hoping he could shake off either his pursuer or his sense of foreboding.
The call Mr Tai had received earlier in the evening - on top of the mysterious appearance of cash in his bank account - made him wonder if he was being lied to.
While he hated the very idea of searching Ethan's room, it was his duty to find out what was really going ... His thoughts trailed off as he emptied the washing bag onto the floor and a blood-soaked T-shirt and trousers tumbled out.
Ethan had one last look back before ducking through the hole in the wire fence. Had something just moved in the shadows beyond the reach of the streetlight? He wasn't sure and, aware what lay ahead for him, he no longer cared.
As he pushed open the door of the crumbling warehouse, the foreman looked up from the fish he was gutting. "Where the hell have you been?"
Ethan didn't explain that he'd dozed off over his homework, instead he just muttered, "Sorry".
The foreman threw an apron at him and jerked his thumb at the rest of the night shift who were already slicing their way through barrels of semi-rotting seafood.
The hours of sleep lost slaving in this god-forsaken shed, on top of the constant anxiety about his Mum's condition, had weakened Ethan to breaking point. Soon the smell of decay and the sight of blood and entrails smeared across the tables, and on his fellow workers' aprons and clothes, began to turn Ethan's nausea to light-headedness.
From his hiding place behind a stack of disused and rusting barrels, Sam gasped as Ethan staggered and dropped his knife to the floor.
After Sam's faltering telephone conversation with Ethan's grandad, it was clear his best friend had been going out every evening and lying about his destination. But while tailing him - and even as he had crept in through the side door of the warehouse - Sam had never expected ... this. The only thing now clearer was the source of the odour that clung to his pal.
"Pick it up," barked the foreman.
Bending to retrieve the knife, Ethan lost his balance and pitched forward onto his face.
Scrambling to see what had happened, Sam slipped on the slime-slicked floor and sent a barrel clattering off the stack. Ethan looked up from his prone position. "Sam?"
"Sam? Now you're bringing your friends here?" Bewildered, the foreman's head began to swing backwards and forwards between the pair as if watching a tennis match. "Do you know him?" he asked Sam who had clambered to his feet.
Confused, Sam replied in his broken Cantonese, "Yeah ... same school", before realising this may not have been wise.
The foreman spun back to Ethan enraged. "Wah! You're a school kid? Not an illegal immigrant?"
Sensing that this could turn ugly, Sam hauled Ethan upright. As the teenagers ran, the foreman called to his assistant. "Lock the door!"
Their exit blocked, the pair skidded to a halt. Hearts pounding, they turned slowly, to be confronted by the advancing foreman, his fish knife glinting in the harsh light.
To be continued next week