ROCKLAND (CBS) – On Friday, 2-year-old Gracie Murray will be giving a very important gift to her little sister Maddie, who has been undergoing chemotherapy for five months now on the heels of a devastating leukemia diagnosis.

Miracle For Maddie Fundraiser: Website | Facebook

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“It just knocks you over, because you never thought about her not living,” said Michael Murray, the girls’ father.

Last summer, Maddie’s mom took her to the doctor for a low-grade fever and some unusual bruising. Maddie then got a blood test and was immediately rushed to Children’s Hospital to begin treatment for acute lymphoblastic leukemia (ALL).

WBZ-TV’s Ken MacLeod reports

Maddie’s mom moved into the hospital, as Maddie’s doctors battled her blood cancer into remission.

“She still keeps going strong. The doctors have been amazed by her spirit,” said Nancy Murray, the girls’ grandmother.

But, the cancer will almost certainly return without a bone marrow transplant, which would boost Maddie’s chances of beating the disease to 60%.

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Her sister Gracie, who is one year and one week older than her, is coming to the rescue. She’s a perfect match.

At age 2, all Gracie knows is that she’s going to the hospital to help her sister.

There’s no explaining the science or the gut-wrenching emotion.

“It just turns out she’ll be the one that saves her life, so yeah, it’s remarkable,” said Michael Murray.

WBZ NewsRadio 1030’s Doug Cope reports

Success would mean two more hospital months for Maddie and six more months quarantined with family at home in Rockland while her battered immune system recovers.

“I feel that she’s gonna beat it and that she’s going to be a little girl again,” said Michael Murray.

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The Murray family is planning a fundraising event for Feb. 11 at the Quincy Marriott.