"I'm going to ask this one final time," said Rainbow Dash, "Have. You. Seen. My. Sunglasses?"

Derpy looked at the MISSING poster in Rainbow Dash's hooves with her crossed eyes. It bore a picture of very professional looking sunglasses with the caption "Reward: 50 bits".

"I am deeply confused and do not understand what it is you are asking," said Derpy, "You're not wearing sunglasses."

Rainbow Dash gritted her teeth and rubbed her muzzle for the umpteenth time. "That's because I LOST them!"

"Why?"

"How-" Rainbow Dash stopped and began to fly away, "Nevermind Derpy..."

Derpy flew after her. "Wait!"

Rainbow Dash turned and sighed in exasperation. "Yes?"

"I can try to find them for you!"

"My sunglasses? Uh, Derpy, I don't think-"

But Derpy was already gone. Rainbow Dash sighed a second time and flew away. She wasn't soaring above the clouds for ten minutes before Derpy returned and flew to her.

She stopped in front of Rainbow Dash suddenly and smiled brightly, her crossed eyes looking at her. She was wearing a stereotypical detective's fedora, complete with a small note pad on it that bore a 'DD'.

Rainbow spoke. "...DD?"

"Detective Derpy!" said Derpy loudly and proudly. "I'll find your sunglasses Rainbow Dash!"

"Derpy, you don't need a hat-"

Derpy got up in Rainbow Dash's face with an angry look. "What do you mean 'Don't need a hat'? I'm a detective. Detectives wear hats. I'm wearing a hat. Do the math!"

"I, er... what?"

Derpy backed up. "I'll be getting those fifty bits to pay for detective pants too! Picture me in pants, Rainbow Dash!"

Derpy spun and did a pose, making Rainbow Dash giggle a bit.

"Fine, if you really want to try to find my sunglasses..."

"I won't let you down, Rainbow Dash!"

Derpy flew away haphazardly, making sure she would find her friend's sunglasses.

Rainbow Dash shook her head. "This is going to be trouble..."

Derpy sat suspiciously at an outdoor cafe and watched, with crossed eyes, as ponies walked around Ponyville doing their daily activities. The day was partly cloudy, some streaks of sunlight reflecting off of Derpy's notepad, perched on her detective hat.

Derpy got out her small recorder and pressed the record button, not taking her eyes off of the ponies, who may have stolen her friend's sunglasses.

"Tuesday... or maybe it's Wednesday... I need to ask somepony..."

She removed her hoof from the record button and approached a nearby pony. "Excuse me sir, what day is it?"

"Wednesday."

Derpy went back to her seat and pushed the record button again.

"Wednesday! Somepony stole Rainbow Dash's sunglasses, and I'm going to find them. I'll bring that pony... to justice!"

She hit the table hard to emphasise her point, sending a hot cup of coffee into the air and making it spill all over somepony's head, burning them.

"MY EYES! THEY BURRRNNN!"

"Aw... my Justice Coffee..."

Derpy left the cafe without coffee, saddened it was all gone. While some ponies tried to calm down the screaming mare covered in hot coffee, Derpy took off flying.

"Okay... who to ask for leads... Rainbow Dash is friends with..."

Pinkie Pie and Twilight were at Sugarcube Corner when Derpy kicked in the door, an angry look on her face.

"STOP RIGHT THERE, CRIMINAL SCUM!"

Twilight fell out of chair in shock and confusion. "Aah!"

Pinkie Pie munched into a cupcake. "Hiya, Derpy! What do you need?"

Derpy walked in and closed the door behind her. "Was that a good Detective Yell? I think it was."

"It was a great yell! What do you think Twilight?"

Twilight rubbed her head. "My ears..."

"Anyway," said Derpy, "I'm looking for Rainbow Dash's glasses. As you can tell from my hat and my Detective Yell, I'm assigned the case."

"Ooh, cool! Can I be your Detective Assistant?" said Pinkie Pie.

"No," said Derpy in a sudden deep voice, "I work alone."

"Aww..."

"I'm kidding, of course you can be my assistant!"

"Yaaay!"

Derpy and Pinkie danced around while Twilight recovered from all the loud yelling.

"Okay," said Twilight, "You said you were trying to find Rainbow Dash's sunglasses?"

"Yep!"

"What locations have you checked?"

"This one."

"...well uh, have you asked Rainbow Dash where she was when she lost them?"

"Nope!"

"Derpy, you aren't making this easy..."

"What time is it?"

"12:30, but-"

Derpy narrowed her eyes at Twilight and got out her recorder.

"Wednesday, 12:30. Twilight doubts I can do my job. She's due for interrogation..."

"Derpy, I'm right here!"

"Maybe hot wax..."

"Derpy!"

Derpy looked up and hid her recorder with a sheepish smile.

Twilight sighed. "You should ask her, or ask the Wonderbolts. She's always hanging around them."

"Good idea! Let's go, my earth pony assistant!"

Pinkie Pie descended her stairs wearing nerd glasses, complete with tape.

"Let's do this!" she exclaimed.

Derpy and Pinkie rushed out of the bakery, leaving a confused Twilight behind.

"Does this mean I won't get my pastries?"

"Let's ask the Wonderbolts!" said Derpy.

"I'll go ask Rainbow Dash!" said Pinkie.

"We'll meet at the cafe when we're done?"

"Uh-huh!"

And so the two detectives went off, determined to prove themselves.