"Accio Cloak!" one of the Death Eaters roared.
Harry grabbed at his Cloak, but it made no attempt to escape. Penelope resisted the urge to let out a breath of relief. The Summoning Charm had not worked on it.
"Not under your wrapper, then, Potter?" The Death Eater turned to his friends. "Spread out. He's here."
Six of the Death Eaters ran straight at them. Penelope, Ron, Harry, Venus, and Hermione backed up as quickly as possible down the nearest side street, the Death Eaters missing them by inches. They all waited in the darkness, listening to the footsteps running up and down and watching the beams of light fly along the street from the Death Eater's searching wands.
"Let's just leave!" Hermione whispered. "Disapparate now!"
"Great idea," Ron replied.
"We know you're here, Potter, and there's no getting away!" a Death Eater shouted. "We'll find you!"
"They were ready for us," Harry stated. "They set up that spell to tell them we'd come. I reckon they've done something to keep us here, trap us—"
"What about Dementors?" another Death Eater suggested. "Let 'em have free rein, they'd find him quick enough!"
"The Dark Lord wants Potter dead by no hand but his—"
"—an' Dementors won't kill him! The Dark Lord wants Potter's life, not his soul. He'll be easier to kill if he's been Kissed first!"
"Shit," Penelope cursed, because if they had to repel Dementors that meant casting a Patronus, which would definitely give them away.
"We're going to have to try to Disapparate, Harry!" Hermione urged.
Even as she said it, Penelope started to feel the unnatural cold sweep over the street. Light was sucked from the environment all the way up to the stars, which vanished. Penelope gripped her wand tight and grabbed onto Ron in the pitch-blackness. They turned on the spot, but the air that they needed to move became solid — they could not Disapparate. Apparently, the Death Eaters had casted their charms well. Penelope, Ron, Harry, Venus, and Hermione retreated down the side street, their hands sliding against the wall, trying not to make a sound. The cold was biting into Penelope's skin, and she watched as about ten Dementors glided noiselessly around the corner. They were only visible because with their black cloaks and their rotting hands, they were of a denser darkness than their surroundings. The Dementors seemed to be coming more quickly now, taking in dragging, rattling despair.
Harry then raised his wand. "Expecto Patronum!"
The familiar silver stag burst from his wand and charged straight at the Dementors. They scattered, and there was a triumphant yell from somewhere out of sight. 
"It's him, down there, down there, I saw his Patronus, it was a stag!"
The Dementors had retreated, the stars were coming out again, and the footsteps of the Death Eaters were becoming louder. Before any of them decided on what they could do, there was a grinding of bolts nearby, and the door to the place Penelope had originally wanted to go opened.
"Potter, in here, quick!" a familiar rough voice ordered.
Penelope couldn't help the smile on her face. The five of them hurtled through the open doorway.