Nicole Moore had just finished playing beach volleyball at a resort in Cancun, when she went into the water to rinse off some sand.

Moments later, she was locked in the death grip of shark and was fighting for her life.

The Orangeville, Ont., woman describes her harrowing encounter from four years ago in a new book called "Shark Assault: An amazing story of survival," co-authored with Peter Jennings.

Speaking to CTV News Channel alongside Jennings, Moore said just before the attack, she heard two men on Sea-Doos yelling and screaming at her, but she didn't know why.

It wasn’t until later that she found out the men had seen two sharks in the shallows and had whistled swimmers out of the water at a neighbouring resort. Moore said they were attempting to corral the sharks into deeper water but ended up steering them in her direction.

And as Moore turned around and started to walk to back to shore, she immediately "felt a bump" behind her, causing her heart to sink.

"Seconds later, I felt a bite to my left upper-thigh -- it bit clean through, just like it was going through butter," said Moore.

"I didn’t see the shark but instantly I knew what it was, and the water started to fill with my own blood within seconds."

Moore said that her brain immediately kicked into "fight-or-flight" mode and she knew she needed to get out of the ocean.

At the time, she was unaware of the extent of the damage done to her leg and she said her fear of the presence of her blood in the water pushed her forward.

That's when the shark came back, sinking its teeth around her entire left arm.

"It is fighting and it is trying to get me down – just thrashing in this water," she said.

"And instinct hit, and I just hit on its nose and pulled my arm out. Fortunately, it opened up its jaws and let go."

The men on the Sea-Doos arrived and pulled her ashore, but the damage was done.

"That's where the fight for my life really began – on that beach," she said.

Despite efforts to save her left arm, doctors were forced to amputate the limb above the elbow. Her leg wound was also slow to heal, and her injuries left her in considerable pain.

But the mother-of-two has persevered and says that despite the frightening experience, she does not have post-traumatic stress disorder or any nightmares about sharks.

Moore hopes that her tale of survival will help inspire others to maintain hope through their own struggles.

"I'm just an average person … that was forced to face extraordinary circumstances and I made it," she said.

"And if I can make it, then no matter what anyone else is facing, they can get through it as well."