"Rio has always dreamed of leaving the underwater city of Atlantia for life in the Above; however, when her twin sister, Bay, makes an unexpected decision, Rio is left stranded below where she must find a way to unlock the secrets of the siren voice she has long hidden and save Atlantia from destruction"--

On the planet of Petaybee, when a visiting scientist discovers the shapeshifting talents of the Shongili twins, who are able to tranform from human to seal and back, the twins are in danger of kidnapping and must flee their home.

Thirteen-year-old Johnny searches the town after his twin sister Alyssa disappears on her way home from the library one day, and Detective Clyde Hunt, lead cop on the case, watches over Johnny and his mother to keep them safe while the boy and his friend continue their hunt.

After seeing a girl who looks just like herself in a violent video, Emma, who lives with a foster family, begins a search to find out what happened to the girl.

"As the exiled Queen of Faerie, Jude must travel back to Elfhame to help her twin sister, Taryn, and uncover how to break a dark curse threatening the whole Faerie world."--

Chris, Cathy, and the twins are to be kept hidden until their grandfather dies so that their mother will receive a sizeable inheritance, however, years pass and terrifying things occur as the four children grow up in their one room prison.

Sixteen-year-old identical twin daughters of a district court judge and a candidate for the United States House of Representatives, Kaeleigh and Raeanne Gardella desperately struggle with secrets that have already torn them and their family apart.

In Rainbow Rowell's Fangirl, Cath is a Simon Snow fan. Okay, the whole world is a Simon Snow fan, but for Cath, being a fan is her life-and she's really good at it. She and her twin sister, Wren, ensconced themselves in the Simon Snow series when they were just kids; it's what got them through their mother leaving. Reading. Rereading. Hanging out in Simon Snow forums, writing Simon Snow fan fiction, dressing up like the characters for every movie...

While true-crime afficionado Ellery and her twin brother are staying with their grandmother in a Vermont community known for murder, a new friend goes missing and Ellery may be next.

Avoiding relationships to protect her sensitive heart, plus-sized Molly supports her once-cynical twin, Cassie, when the latter has her own bout of lovesickness, a situation that is complicated by sibling dynamics and an unexpected romantic triangle.