In 2008, Christina Applegate was diagnosed with breast cancer at just 36 years old. She underwent a double mastectomy, survived, and rebuilt her life. Thirteen years later, another devastating diagnosis would begin dismantling almost everything she had fought to preserve.

Christina Applegate has already survived cancer, undergone a double mastectomy, and watched a celebrated acting career slip away because of illness.

Now she faces another terrifying medical uncertainty.

The woman who spent five years learning to live with a devastating diagnosis must begin searching for answers all over again.

And this time, she doesn’t even know what she’s fighting.