[Author’s Note: Some artistic liberties have been taken.  Gemma’s letter to Father Germano is verbatim, but because we do not know anything about the night before the devil began his Hellish campaign against her, the opening scene is my interpretation of how Gemma would come to terms with what awaits her.  The flashback to 1899 is also accurate with two exceptions.  Satan did offer to cure her, but what exactly was said was not documented.  Also, Gemma called out to then-Venerable Gabriel Possenti twice, but in the flashback, I shortened it for the sake of brevity].

“Jesus, make haste, give me the grace to be ever united with You, in such a way that I may never be separated from You.”
–Saint Gemma Galgani

Lucca, Italy – 1902

“Dear Father Germano…”

Her pen gripped in her trembling hand, Gemma Galgani begins her letter.

“During the last two days Jesus has been telling me after Holy Communion: ‘My daughter, the devil will soon wage a great war against you.’”

She pauses, lifting her eyes to the dancing firelight of her candle.  She rests her jaw in the palm of her hand, listening to her own increasing heartbeat.  After a moment, she resumes writing:

“These words I hear in my heart continuously.  Please pray for me….”

A sudden chill overcomes the room.  Gemma rises from the small table.  She wraps herself in her black mantellette robe.  The cold persists, but the fabric of the mantellette keeps in the warmth.  She sits herself down and presses on with her letter:

“Who will win this battle: the devil or my soul?  How sad this thing makes me!  Where will the war come from?  I am for ever thinking about it instead of praying Jesus to give me strength and help.  Now I have told you, and I leave this matter to you, that you may help me.

Your poor,

Gemma.”

The pitch blackness of nightfall makes her window look like a square hole into an unknown abyss.  Gemma stands up and walks to the window, focusing her eyes on the scattered stars.  She leans forward and rests her arms on the window frame.  Ashen clouds curtain the full moon, engulfing the stars.
Her head lowers, “Jesus, am I truly ready for this coming trial?” She places her hand on her forehead as anxiety races through her mind.  “What if–” she hunches forward, crossing her arms.  “What if the devil overcomes me?” As her eyes swell with coming tears, she looks at her bed.  “To think that I almost gave in…” she closes her eyes as the memory of her weakest moment overwhelms her, a seemingly ancient time when illness had crippled her and made her susceptible to the darkest temptation.

1899
“My, my, you poor thing…” a wicked voice echoed from the shadows of her room.
Gemma sat up, turning her head as her weary eyes scanned the room.  “Who…who is th-there?” Succumbing to the pain in her spine, she lay back down.
“Tsk tsk tsk, to say that you are not looking well would be an understatement, now wouldn’t it?” The dark figure took form.  Gemma forced her eyes open and stared at the being, a muscular angel with folded wings and small horns.  His skin and talons the color of shadows, his fiery eyes bore into hers.
Gemma couldn’t stop her body from shaking.  “You–you’re…Lucifer.”  Her blood froze at the sound of his laughter.  “Ah, I haven’t heard that name in a long time,”  Satan reached out his hand to touch her forehead.  Gemma turned her head away.  Were it not for her afflicted spine, she would have turned her back to him.
“I mean you no harm, dear child.  Quite the contrary,” Satan wandered around her room.  Relaxing her body, Gemma watched him cringe at the crucifix on her wall.  She looked away when he faced her.
“Ignoring me is not going to make me disappear, little one,” Satan narrowed his eyebrows, staring her down the way a lion faces its weakened prey.  He paced back and forth, “As a fallen angel, I may not be on good terms with your friend,” he pointed at the crucifix, “…but I still have all kinds of powers.  If you were to give me a chance, I could cure you.”
Beads of sweat drenched her forehead and ran down her deathly pale face.  Clutching onto the sheets, Gemma grinded her teeth as she endured the terrible pain.  Her eyes watered as her vision blurred from the pounding migraine.
Satan’s mouth lifted into a sinister grin, “I can take away your suffering, Gemma.  Whatever you desire, I will grant you.  If you submit to me, obey me, do as I say, I will see to it that your body never betrays you again.”  He opened his palm and reached out to her.  “Just take my hand and I will free you from your misery.”
Gemma kept her eyes on the ceiling.  Desperation began to drown her.  As if her body was moving without her consent, her hand lifted.  She pulled back, clenching her fist.  She relaxed her hand, leaving it mid-air.
At that moment, a face appeared before her mind’s eye. 

Venerable Gabriel Possenti…the holy boy she had read about.  His figure covered in light, his soft brown eyes gazed into hers.  For a moment, she forgot that the prince of darkness was standing at the foot of her bed.
Gemma inhaled through her nostrils.  With a cold-stone expression on her face, she realized that she was at a crossroads and only one path could be chosen.
A guttural cry escaped from her, “Venerable Gabriel, save my soul first and then my body!”  With that hand that almost ended up in Satan’s grasp, she made the sign of the cross as fast as she could.
There was a flash of light, followed by a furious scream.  When the light disappeared, so had the enemy.

Gemma raises her eyebrow.  “Hmm, how odd, I don’t remember blowing out the candle…” she looks curiously at the extinguished candle.  The frail line of smoke disappears into the air as it floats from the charred wick.
She gasps as she looks around the darkened room.  She takes a deep breath to calm her nerves.  “All right, if this is what You want, Jesus…” she pauses, staring straight into the shadow that has engulfed her door.  “…then I want it, too.  So long as You give me the strength to stand my ground against him.”
Gemma curls up on her bed.  Weariness presses down on her, pushing her into a deep slumber.  The last thing she sees is a shadowy figure standing by the window.