Grissom walked with the Doctor and Sherlock toward the area where they were the night before. Upon reaching where the Plague Doctor was standing, Grissom knelt down and looked around. He gestured with his hands, "He stopped here, correct?"

"Right," both the Doctor and Sherlock nodded. Grissom narrowed his eyes and pulled out a pair of tweezers and prodded an area of the rubbish bin near him. He pried from the crevices of the wheel a carrion beetle, just like the one he had dissected earlier. However, Grissom studied it and concluded it was dead; a milky substance coated the amber eyes. The Doctor tilted his head, "It could've died days ago."

Grissom raised the beetle carcass toward the sunlight. He replied, "It died at most two weeks ago."

"Impossible," Sherlock shook his head. He was going to say that it would've been impossible for the beetle to been there for two weeks, the Plague Doctor had been in his and John's universe for quite some time, however he was silently advised by the Doctor to not disclose that fact at all, as it would be an unwise decision. The Doctor looked at Grissom and crossed his arm, "Can you tell how it died?"

Grissom nodded and brought out a small scalpel he kept on his person for occasions such as this. He held the tweezers in one hand as he cut the carcass in the other. No amber substance poured out like the one in the lab, but what's more is he couldn't find anything at all, nothing. Grissom concluded, "It starved."

"Not many carrion out in this area for it to feed on, I'd say," the Doctor commented. Sherlock blinked, "What do you think?"

"Protocols," Grissom responded as he collected the carcass as means for his theory. His theory would sound outlandish at best but for the sake of being, any theory's better than none. He still needed more time to smooth the theory out before he even mentions it.

They continued to survey the area, looking for anything dead that the beetles might've taken to. Grissom looked up to spot a nest perched in a cider tree and pointed, "They tell me it has ravens, correct?"

"Yeah, smart bastards, they are," the Doctor nodded. Grissom rubbed his beard. "If the beetle came from it, then the ravens might help too," he told them. Sherlock blinked, "Help?"

"I believe there is some sort of co-operative gambit with the beetles and the ravens. Ravens are extremely intelligent; they follow this thing verbatim. Beetles go where there is food, ravens are opportunistic, mix them together and you'll get," Grissom reached up to the nest and pulled out the remains of a carrion beetle, "A full circle. Beetles invaded the interior of the machine, ravens eat the beetles, and ravens stay with the machine and then some."

"It's brilliant," Sherlock stared. The Doctor nodded. Grissom looked at the halved thorax, "But it doesn't answer all my questions though."

He was looked at and he sighed, "Protocols."

Going by the reports that were given, they headed toward the riverside where it was said that one night a man and his son both witnessed someone near the rafters, there were ravens apparently diving into the waters and bringing up fish. They did not see the person entirely, as it was pitch dark, but it was good enough for them to investigate. Upon arrival to the riverside, they headed toward the rafters. Grissom's heavy boots sunk into the damp sand as he walked toward the decaying corpses of what looked like fish. Flies flew around as he knelt beside one and studied it, the fish had been pecked at by the ravens and he spotted crawling around what remained of the gills something small. With his tweezers, Grissom prodded the corpse until he pried away from the rotted flesh a carrion beetle. He held it up for the Doctor and Sherlock to see, "Found one."

"How many do you need?" the Doctor asked him as he collected the beetle. Grissom sighed in response, "Enough for a theory."

Sherlock's attention was pulled away from them, glancing over to where Big Ben was supposed to be, only to find that in its place a Churchill memorial had been placed instead. The Doctor caught him looking and shook his head and privately told him, "In every universe a variable changes. Sometimes it's small, but in some cases it can be big."

"Why does this London have a Churchill memorial?" Sherlock asked him. He groaned, "Oh, yeah, the Daleks. Oh, don't worry; they're not a problem—at least for now."

"Daleks," Sherlock tilted his head. The Doctor waved his hand, "I wouldn't ask. They're not in your universe. Be thankful they're not; they're a bane of me. Think flying rubbish bins with a nasty attitude."

Grissom continued to study the carcasses of fish, digging around for any living carrion beetle. So far he had only found two and they were small—indicating that they weren't hatched too long ago. He studied them before he tucked them into a specially made container and stood up, patting the sand off his pants. Grissom sighed as he glanced at the beetles as they maneuvered around the container, confused. "A male and a female, it looks," he told them as he rejoined the two's side while holding up the container. "Lovely, do you still need more?" the Doctor asked him. Grissom nodded and stopped before asking Sherlock to hold the container for a minute as he needed to contact UNIT for something. Sherlock held onto the container, looking at the beetles as they moved around. Their amber eyes glistened in the sunlight as they tried to escape the container; they were covered in blackened gunk, likely from the fish carcass. He tilted his head as they settled near the corner of the container and stared, at him.

The Doctor leaned near Sherlock to look at the beetles and shook his head. "Ugly things, they are," he commented. Sherlock nodded, "They do serve a purpose nevertheless."

"Yeah, a purpose," the Doctor coughed. Sherlock glanced at him, "What do you think?"

"Oh, I don't bloody know. There's no way a murder of ravens would follow that thing, beetles or not," the Doctor sighed. Sherlock nodded, "There's something else involved, isn't there?"

"I don't know rightly, Sherlock," the Doctor admitted.

Grissom stepped away from them again, far enough so they wouldn't overhear his conversation. Nick picked up and Grissom told him, "Find me a normal raven, will you?"

"A raven…?" Nick questioned. Grissom sighed, "A normal, non-amber eyed one. I have a theory I want to test."

"Right, one raven coming right up, would you like a writing desk while we're at it, Poe?" Nick joked. Grissom gave a weary sigh in response. "No, just a raven, stick it in a birdcage and have it in my office by the time I get back, understand?"

"Aye, captain," Nick acknowledged and the conversation ended.