Ninth Key by Meg Cabot

Title: Ninth Key

Author: Meg Cabot

Saga: The Mediator - Book 2

Plot:

Everything is going great for Suze. Her new life in California is a whirlwind of parties and excellent hair days. Tad Beaumont, the hottest boy in town, has even asked Suze out on her very first date. Suze is so excited that she's willing to ignore her misgivings about Tad... particularly the fact that he's not Jesse, whose ghostly status—not to mention apparent disinterest in her—make him unattainable.

What Suze can't ignore, however, is the ghost of a murdered woman whose death seems directly connected to dark secrets hidden in none other than Tad Beaumont's past.

Shadowland by Meg Cabot

Title: Shadowland

Author: Meg Cabot

Saga: The Mediator - Book 1

Plot:

Suze is a mediator -- a liaison between the living and the dead. In other words, she sees dead people. And they won't leave her alone until she helps them resolve their unfinished business with the living. But Jesse, the hot ghost haunting her bedroom, doesn't seem to need her help. Which is a relief, because Suze has just moved to sunny California and plans to start fresh, with trips to the mall instead of the cemetery, and surfing instead of spectral visitations.

But the very first day at her new school, Suze realizes it's not that easy. There's a ghost with revenge on her mind ... and Suze happens to be in the way.

City Of Glass by Cassandra Clare

Title: City Of Glass

Author: Cassandra Clare

Saga: The Mortal Instruments - Book 3

Plot:

To save her mother's life, Clary must travel to the City of Glass, the ancestral home of the Shadowhunters -- never mind that entering the city without permission is against the Law, and breaking the Law could mean death. To make things worse, she learns that Jace does not want her there, and Simon has been thrown in prison by the Shadowhunters, who are deeply suspicious of a vampire who can withstand sunlight.
As Clary uncovers more about her family's past, she finds an ally in mysterious Shadow-hunter Sebastian. With Valentine mustering the full force of his power to destroy all Shadow-hunters forever, their only chance to defeat him is to fight alongside their eternal enemies. But can Downworlders and Shadowhunters put aside their hatred to work together? While Jace realizes exactly how much he's willing to risk for Clary, can she harness her new found powers to help save the Glass City -- whatever the cost? 

City Of Ashes by Cassandra Clare

Title: City Of Ashes

Author: Cassandra Clare

Saga: The Mortal Instruments - Book 2

Plot:

As readers of series starter City of Bones already know, teenager Clary Fray is a Shadowhunter, a demon slayer who has the gift of spotting Downworlder werewolves, vampires, and faeries. She is also an adolescent in an abnormally dysfunctional family: Her mom is in a magically induced coma and her father is probably insane and undoubtedly evil. All of which places Clary in situations that would challenge even the most talented average American girl.