Captain Colossus and the Runaway Train

It started with a simple job.
At least, that’s what his Mum said.
“All you have to do, Jamie,” she told him in the supermarket car park, “is push the trolley to the trolley park. Carefully.”
Jamie nodded with the solemn responsibility of a man entrusted with a mission of great importance.
Zip trotted alongside, ears alert, well, one ear alert, the other ear doing its usual flopped-over thing.
The trolley looked harmless enough. But as Jamie wrapped his hands around the handle, one of the front wheels gave a suspicious wobble.
“Hmm,” Jamie muttered. “Suspicious activity.”
Then the slope of the car park revealed itself.
And the trolley rolled.
And Jamie ran.
And the trolley rolled faster.
“Woooaaahhh! ZIP! IT’S GETTING AWAY!”
Cars blurred past. Zip barked encouragement (or possibly alarm). The trolley rattled and clanged, wobbling violently as Jamie’s feet slapped against the tarmac.
And then... the world shimmered.

Jamie was no longer a small boy in a supermarket car park.
He was Captain Colossus, Hero of the Infinite Realms, standing on the roof of a roaring steam engine hurtling along the Endless Tracks of Peril.
Wind whipped his black cape. Smoke billowed. Below, terrified passengers clung to their seats as the train thundered toward a shattered bridge high above the Canyon of No Return.
Beside him, Zip was no longer scruffy, he was a sleek black German Shepherd, muscles coiled, eyes scanning for danger.
“Engineer’s been kidnapped by the Iron Bandits!” Zip barked in a voice that made perfect sense in the dreamworld.
“Then we take the controls!” Captain Colossus bellowed. He charged across the roof, leaping carriages, dodging swinging chains and flying sparks. The engine screamed around a bend, rails groaning under the strain.
Finally, he burst into the locomotive’s cab.
The controls were tied up with thick, oily ropes.

The Iron Bandit leader, all jagged teeth and glowing red eyes, stepped forward.
“Too late, Colossus!” the villain roared. “The train will plunge into the canyon, and your legend will end!”
Colossus grinned. “I think… you’ve missed a stop.”
With one mighty punch, he sent the Bandit flying into a hay cart conveniently parked beside the tracks. Zip bit through the ropes, freeing the controls. Colossus yanked the brake lever back, sparks flying, wheels screaming...

...and the trolley clanged into the trolley park.
Jamie stood panting, hands gripping the handle, Zip wagging furiously. The trolley wobbled to a stop, one wheel still squeaking in protest.
Mum strolled up with the shopping bags. “What took you so long?”
Jamie gave her a small, knowing smile.
“Had to save a few lives, that’s all.”
Zip barked once. The bent ear twitched like he knew the truth.