Well, here we go. I decided this was the next story that had to be finished, even though Something Special is set earlier. Mainly that was because this one is T rated, while Something Special will be M rated and I know at least some of my audience doesn't want that.

Credits: some minor ideas are borrowed from karly05 and Lowrider; they're marked at the end of the chapter they first show up in.

Notes: I suspect the science in this is pretty awful. I'm a computer scientist, not a biologist.

Warnings: While I'm pretty sure this is clearly in bounds of a T rating, there are a couple mentions of seventeen-year-olds having sex (off screen), which may be more than some readers want. There is absolutely nothing even remotely explicit in this story.

Dedication: For my mother, taken from us too early by lung cancer. If only there were a real life Phineas and Ferb who could save lives like this.

Timeline: Summer between Phineas, Ferb, and Isabella's junior and senior years of high school, after Phineas's birthday. Phineas and Isabella are seventeen, Ferb is sixteen.

Isabella had been dragged out to the dress fitting with Candace's other bridesmaids: Stacy, Jenny, and Susan, a friend of Candace's from college. Candace's wedding had been accelerated due to an unexpected pregnancy, so tasks that everyone had thought they had a year to complete suddenly had to be ready for the big day in just three weeks. Fortunately, Candace had everything planned already; it was just a matter of execution.

Isabella pondered what she was going to do in the afternoon - her boyfriend Phineas and his brother Ferb were off with Candace's fiancé, Jeremy, for tuxedo fittings, and weren't expected back for an hour or two. Maybe she'd just sit out by the pool and enjoy the warm late-summer day until Phineas got home, and then...well, two seventeen-year-olds with the house to themselves could certainly find something to do. The couple had become lovers just a couple weeks previously, on Phineas's seventeenth birthday, after dating for two years.

As expected, the house was empty when she arrived; her father, Samuel, was at work and her mother, Vivian, had a doctor's appointment for a breathing problem she'd been having recently. Isabella put on her white bikini and brought a glass of lemonade and her cell phone out to the pool to await Phineas's return.

Her phone rang. Silently, she hoped it wasn't Gretchen. She and Ferb had broken up a week earlier after going out for a month, and while they had both claimed it was a mutual decision, they both seemed to be taking it harder than anyone expected. Isabella had spent much of the past week consoling her friend and reassuring her that she'd find the right guy eventually; for some reason this just made Gretchen sadder. A quick glance said that it was her father instead.

"Hi, Dad. What's up?"

"Isabella, are you at home?"

"...yeah, why?"

"You need to come to the hospital. They found what was causing your mother's breathing problems. It's...just come."

"You and Mom have the cars. Should I take a taxi, or wait for Ferb to get back? He can give me a ride."

"How long until Ferb gets back?"

"They should be home any minute...actually, I think I hear him pulling in."

"Okay. Get here as soon as you can."

Wishing it had been Gretchen after all, Isabella went out the gate of the back yard and saw Phineas and Ferb getting out of Ferb's hand-restored hot rod. Phineas smiled to see her, but then his eyes narrowed at the look of concern on her face.

"Ferb, can you give me a ride to the hospital? Apparently my mother's been admitted with breathing problems."

"Certainly," Ferb said. "Would you like to go change first?"

Isabella looked down, realizing she was still in her bikini. "...yeah, that'd probably be a good idea. Be right back."

Phineas and Ferb followed Isabella through the halls of the hospital. Finding the right room, they found Vivian lying in a hospital bed looking pale and exhausted. Samuel sat in a chair next to her, holding her hand. Isabella took her mother's other hand and sat on the edge of the bed.

"So, what's wrong?"

Samuel looked at Isabella, his eyes red-ringed from tears. "It's cancer. They're still tracking down where it came from originally, but it's spread to her lungs. That's what was causing the breathing problems."

Isabella's eyes widened as she looked at her parents. "Do they think they can treat it?"

"They're running the biopsies right now, but they didn't seem optimistic. It depends what they find."

A tall black woman entered the room wearing a white coat and carrying a clipboard. "Hi, I'm Dr. Washington. You must be Mrs. Garcia-Shapiro's daughter? She mentioned you, and her son-in-law...?" She looked back and forth between Phineas and Ferb.

"Future son-in-law," Phineas said, giving Isabella an embarrassed smile. "We're just seventeen. This is my brother; he gave us a ride here."

The doctor nodded. "I'm sorry, she just referred to you as mi yerno..."

Isabella blushed. "She does that."

The doctor smiled, then looked at her clipboard. Her expression got more serious, and she said, "The preliminary results came back, and they don't look good, unfortunately. The cancer has metastasized from her liver into her lungs and possibly other organs. Unfortunately, this type of cancer doesn't respond very well to chemotherapy - the effective dose required is too high. It intertwines itself with vital healthy tissues, so we can't just cut it out or kill it with radiation therapy. It's pretty much beyond the capabilities of conventional medicine to deal with."

Samuel looked over at his wife, looking shocked and pale in the hospital bed. "There's really nothing you can do, then, is there?"

"I'm sorry, Mr. Garcia-Shapiro. We're going to keep looking into our options, and these are just preliminary results - maybe the final results will be more promising." Isabella's eyes started to fill with tears as she gave her mother a desperate hug.

Phineas called the doctor over as she headed away. "Hypothetically, if there were something that could go in - a small probe, say - that could physically target the cancer cells, could that help her, or would the damage be too great even with that?"

The doctor thought. "I think it would help, but it's hard to tell if it would be enough. The cancer cells might leave gaps between other vital cells, and regrowing cells to fill them would take time, but it certainly wouldn't hurt her any more than the cancer does. But it's not like that's even possible."

Phineas smiled. "No, of course not. That would be ridiculous."

The doctor gave him a steady look, then continued on her rounds as Phineas looked at his brother.

"Ferb, I know what we're going to do tomorrow."

Ferb nodded.

Ferb's hot rod borrowed from karly05's Ferbnessa series. Vivian calling Phineas 'mi yerno' ('my son-in-law') borrowed from Lowrider's 'Summer of Love'.

The story of Candace's unexpected announcement, Gretchen and Ferb's brief relationship, and other events from earlier this summer will appear in 'Something Special' when it's finished.