Hold on tight, mystery lovers! The adventure isn’t over yet—The Sullivan Detective Agency: Double Trouble series is back with its thrilling third installment! If you thought the first two books were packed with suspense, twists, and edge-of-your-seat action, wait until you dive into the final clue of Carter and Cooper Sullivan’s most dangerous mystery book series yet!

Get ready once more to join the dynamic twin detectives, their quirky friends, and the ever-helpful (and mysterious) Mr. Amos Murphy as they face their biggest challenge yet. Will they solve the mystery and escape unscathed? Or will the dark secrets they’ve uncovered be their undoing? As part of one of the most popular children’s mystery series, their adventure will keep you on the edge of your seat. Keep reading to find out!

What’s the Big Secret at Bloomfield Junior High?

You know how sometimes you walk through your school and feel like there’s something hidden in the walls? That’s exactly how Carter and Cooper Sullivan feel about their school in Bloomfield. Everyone whispers about a hidden basement beneath their school—no one really knows what’s down there, but rumors about a mysterious sarcophagus are enough to make anyone curious!

So, what do Carter and Cooper do? They set out on a mission to find the hidden basement and uncover the truth. But here’s the catch—who is trying to stop them from discovering what’s beneath their school?

How Did They Find the Secret Staircase?

After weeks of looking for clues and following the mystery, Carter and Cooper find a locked door in the school’s basement. Inside? A secret staircase that leads to… who knows where! They finally crack the code and enter, but what they find is nothing like they imagined.

What’s waiting for them? Could there be a treasure hidden down there, or is something darker and more dangerous lurking in the shadows?

Why Does Mr. Amos Murphy Want to Help?

Just when the twins think they’ve got the mystery all to themselves, guess who shows up? Their quirky, retired detective neighbor, Mr. Amos Murphy, who insists on joining the investigation. Why? Because he knows something the twins don’t: there’s more to this mystery than meets the eye.

But is Mr. Murphy really just a helpful old detective, or is there something he’s not telling them? What does he know about the sarcophagus that could change everything?

What’s Inside the Sarcophagus?

Here’s the burning question everyone wants to know—What’s inside the sarcophagus?

• A long-lost treasure from centuries ago?
• A cursed artifact with hidden powers?
• A secret that someone will do anything to keep buried?

As Carter, Cooper, and their friends Brody and Kylie get closer to the truth, they realize there are more dangerous forces at play than they ever imagined.

Who—or what—is trying to stop them from getting to the sarcophagus? Why is someone so desperate to keep this secret hidden?

What’s the Twist?

As the team gets closer to solving the mystery, they realize the sarcophagus isn’t the only secret the school is hiding. A series of strange occurrences and clues lead them to believe the mystery goes deeper than they ever thought possible. There are hidden passages, eerie sounds, and a feeling that something—or someone—is following them.

Will they uncover the truth before it’s too late? Or will they get trapped in the mystery forever?

Who Can They Trust?

With danger lurking around every corner, Carter and Cooper must ask themselves—Who can they trust?

They’ve got their friends Brody and Kylie by their side, but can they rely on them when things get tough? What about Mr. Amos Murphy? Is he hiding something from them? And what about the strange figure they keep seeing in the shadows—could it be someone trying to help them, or someone trying to stop them?

Will the Twins Solve the Mystery?

One thing’s for sure—Carter and Cooper Sullivan are not giving up in this mystery book series. They’re determined to solve the mystery and uncover the secret beneath their school. But with every new clue, the stakes get higher, the danger more real, and the mystery even bigger.

So, will they find the truth about the sarcophagus? Will they escape the trap they’re walking into? And most importantly—will they make it out of this mystery alive?

Why Should You Read The Sullivan Detective Agency: Double Trouble?

This isn’t just another mystery. THE SULLIVAN DETECTIVE AGENCY: DOUBLE TROUBLE THE FINAL CLUE (PART-III) will keep you on the edge of your seat, turning pages faster than ever. It’s packed with twists, secrets, and unforgettable characters that will have you hooked from the very first page.

Don’t miss out on the adventure of a lifetime—join Carter, Cooper, and their friends as they crack codes, face danger, and uncover the mysteries. Can they solve the riddle before it’s too late?