The slide was steep and slightly terrifying, and the light from the top receded quickly. It seemed to take an age before Leo hit the ground in a heap. He was in the Chamber of Secrets.
He picked himself up, not stopping to check for injuries (he wasn't the one in danger right now) and cast Lumos so he could see where he was going. Then he walked briskly down what appeared to be a kind of large passageway. As he got further along, he began to hear a thudding noise, and then he recognised a voice yelling, "Oh – come on – Merlin, this is hard work – "
It was, unmistakably, Ron Weasley. At least this meant that he was still alive. "Hello?" called Leo cautiously.
"Who's there?"
"It's me – Asriel – Leo. It's okay, I'm here to – help. Are Potter and Lockhart there with you?"
By this time Leo was close enough to be able to dimly see Weasley's red hair, and Lockhart sprawled on the ground, almost unconscious, nearby.
"Lockhart is – Harry went on – "
Leo reached Weasley, who appeared to be trying to shift a large pile of rocks without his wand.
"What happened?" he asked.
"Lockhart tried to wipe our memories – he's a fraud, didn't do any of the things he said he did, and Harry took his wand and threw it out the window – and we forced him down into the Chamber with us and he grabbed my wand and tried again but it's been broken ever since the incident with the Whomping Willow and it exploded and… this happened." He gestured to the wall of rocks blocking them from going further into the Chamber.
"But… Potter still has his wand, right? Couldn't he have just blasted through – "
"We thought the ceiling would fall down."
"Shield Charms," said Leo. "They'll hold it up enough to keep you safe if it does."
"I don't know how to cast a Shield Charm, Lockhart never taught us anything, and we only have one wand – "
Leo sighed. "Fine," he said resignedly. "I'm going to blast through, but in a controlled way so it won't fall down." He studied the rocks carefully, looking for a spot where it could work. He'd never really studied how to break through a rock wall without causing it to collapse and was mostly making it up as he went along, but he had to get through somehow.
Once he thought he'd identified a weak point, he muttered, "Nox," to put out the light of his wand, and then touched it to the wall. "You might want to get a safe distance away," he said. "Take Lockhart with you, if you want."
Weasley moved back, not bothering with Lockhart, and Leo took a deep breath.
"Bombarda!"
There was a deafening crashing sound. Leo covered his head with his hands, closed his eyes and hoped for the best.
The noise eventually came to a halt, with Leo still feeling more or less alive. He opened his eyes, then realised that it was dark anyway. His wand was still in his hand, so he muttered, "Lumos."
To his pleasant surprise, the rockpile had completely collapsed, but the ceiling hadn't. He stood up immediately and began picking his way through the rocks until he saw a huge green snakeskin lying on the ground. "Basilisks shed their skin, do they?" he asked conversationally.
"Where are you going?"
"Into the Chamber, obviously. You coming?"
Weasley got to his feet, not wanting to be beaten in bravery by a Slytherin, and the pair walked forward together.