When David Goldwasser sat down to write his novel "Portals" he was consumed by the grief of his wife and daughter's deaths, which had happened within five months of each other.  But when he put pen to page what poured out wasn't anguish at all. Goldwasser channeled his love and heartache into vivid sci-fi fantasy. And he did it for them.

An epic fantasy novel inspired specifically by the Bronx native's daughter, Marisa, "Portals," is about a girl named Lissa who discovers she has magical powers while lying on a hospital bed fighting pediatric cancer. Goldwasser wrote the book to fulfill a promise to his daughter he never got to keep while she was alive, writing a sci-fi novel with her.

The promise came from his daughter's love of fantasy stories. Goldwasser had often read Marisa books like "The Hobbit" when she was young, and before he knew it, she was hooked, he told the New York Daily News.

As she grew, Marisa turned into an avid reader, a bright student, and varsity high school athlete. But when she turned 16, she was forced to follow another path when she was diagnosed with Hodgkin's lymphoma. Overnight, Marisa star student was transformed into Marisa the cancer patient. But she didn't let her illness change who she was.

"She was extraordinary," said Goldwasser of his daughter. "She never said, 'Why me?' She just went about making it easier for her friends and family to deal with her chemotherapy and radiation."

Marisa beat cancer at 16, and then beat it again when it returned in her senior year.

When she got accepted to Duke, things seemed like they had finally gotten better, and then the cancer returned. That's when Marisa told her father they should write a science fiction novel together when she graduated from college.

While Marisa was sick, Goldwasser's wife, Sharon, a lifelong diabetic who had suffered a kidney transplant, lost a limb, and developed eye problems, died.

Five months later, he had to go through it all over again.The harrowing cancer treatments Marisa required were too much for her. Soon Marisa grew weak, went deaf, and before the father and daughter could write their novel together, she was gone.

It took Goldwasser until 2008 to sit down and begin writing "Portals." And now with it finished and published, he says he feels like he was working with Marisa the whole time. "We wrote the book together in a very different way," he said.

Goldwasser grounds the fantastical aspects of "Portals" by setting the novel in New York.  His writing is full of the sights and sounds of the city.

"Portals" puts its protagonist Lissa in a fight between good and evil while bringing in real historical events and settings from Goldwasser's childhood neighborhood, including an old amusement park that few remember today. The book is the first in a forthcoming trilogy, which Goldwasser said he likes to imagine that his daughter would like. "I hope I got it right," he said.

The book is garnering mostly positive reviews.

Via Amazon:

"Portals is the type of book that pulls you in and keeps you coming back to read more. The charming, witty heroine, Lissa, keeps you cheering for her the whole way through. Portals will bring you on a journey - emotional, historical, and magical. I loved this book and am on the edge of my seat, waiting for the next one to come out so I can continue to follow the characters that I love." - Amanda C.

"I'm not a science fiction fan but am I glad my friend told me I had to read this book. The combination of a great story, magic and historical commentary made this a most enjoyable read. Congratulations to the author and I hope to see a sequel. lissa reminds me of the heroine in 'The Hunger Games.'" - Bernie K.

"Portals" is for sale in print and e-book editions now. A portion of sales from the novel will go to the Marisa Fund, a charity aiming to raise $1 million for research, treatment, and care for children and families dealing with pediatric cancer.