The Heroes of Olympus

The second series of Percy Jackson books by Rick Riordan

The Blood of Olympus

Sherlock Holmes

If you've never read a Sherlock Holmes book before, I recommend starting with one of the selections, like The Adventures of Sherlock Holmes

Sherlock Holmes - A Study in Scarlet
Sherlock Holmes - The Sign of Four
Sherlock Holmes - The Adventures of Sherlock Holmes
Sherlock Holmes - The Memoirs of Sherlock Holmes
Sherlock Holmes - The Hound of the Baskervilles
Sherlock Holmes - The Return of Sherlock Holmes
Sherlock Holmes - The Valley of Fear
Sherlock Holmes - His Last Bow
Sherlock Holmes - The Casebook of Sherlock Holmes

The Underland Chronicles

The fantasy series by Susanne Collins, author of The Hunger Games

The Underland Chronicles book 1 - Gregor the Overlander
The Underland Chronicles book 2 - Gregor and the Prophecy of Bane
The Underland Chronicles book 3 - Gregor and the Curse of the Warmbloods
The Underland Chronicles book 4 - Gregor and the Marks of Secret
The Underland Chronicles book 5 - Gregor and the Code of Claw