At the end of the day, after several round trips to Earth and a shift on generators, having spent every moment of downtime struggling with the six synergies under Cassandane's critical eye, Sam couldn't wait to recline on her cot. Unfortunately, Cassandane had other plans.

"Your strength hasn't increased in several days," Cassandane told her as they walked back to their home.

"That's probably because training the synergies doesn't use as much precursor."

"I guarantee you it is not." Cassandane stopped walking and pointed at their balcony. "Fly up to it."

With a grim expression, Sam gathered her corona and lightened her weight with as big a counter-push as she could manage, then squatted down and leapt into the air. She made it about halfway to her goal before drifting back to the ground in an asymptotic arc caused by the Angelship's rotation. Sam turned to face her mentor. "I'm close."

"You have been close for a while."

"Then I will work harder at getting stronger."

Cassandane shook her head. "That would only exacerbate the problem. You are at a stage where you need to practice clearing. Paragons are extraordinarily inefficient at drawing forth precursor. The three interact and leave behind massive amounts of residue. That process is sometimes called corrosion, but I don't think that nomenclature is quite accurate, considering it is reversible for us. The buildup takes about thirty years to render someone with a single talent useless -- more or less depending on how hard they push themselves. It takes only about fifteen years to end the career of someone with two talents. A paragon who doesn't practice clearing has only a few weeks of regular use before their talents fail. You, Sam Wilcox, are clogged up."

"Why haven't you been teaching me how to clear all this time?" Sam's voice came out rather more screech-like than she intended. The thought of losing her talents did not make her happy.

"You cannot learn to clear until there is residue built up. The first step is for you to use all three precursors to prod around for obstructions. Then you simply move them out of the way. Does your Earth have plow trucks that clear the roads of snow in the winter? That is what you are doing in step one: pushing residue aside to clear a path for precursor to flow once more. When you have piles of residue built up, we can move onto step two and react them together to get rid of the residue altogether."

Sam pulled out some precursor and began prodding around inside her mind, trying to find whatever was clogging up her system. "I hope this isn't as hard as the other synergies. At least there are only two steps."

"There are three," Cassandane said.

"Oh, joy. What is the third step? Something easy?"

"Something only five Angmari have ever done. Using the reaction of residue to create a self-reinforcing process of precursor generation. I . . . am not optimistic of your chances there, Sam. I will do my best to instruct you, but that is one thing I cannot teach. It requires a flash of insight, of momentary genius, to find a solution. Hafnym was never particularly skilled at any of the talents, yet he managed it. Meanwhile, many brilliant minds have failed to advance as paragons. My own instructor's methods are not worthy of replication, no matter their success. He gave every student of his a single month to ignite. At the end of that trial month, failures were tortured to death in brutal fashion while the rest of us who had yet to succeed watched on in horror. The stress destroyed many, but it gave others of us an intensity of focus we could never achieve without the terror imposed upon us. I will not murder you, Sam, and I won't even try to trick you into believing otherwise."

Sam pointed up at the balcony. "Are you going to help me up tonight or do I have to sleep down here if I can't pass your test?"

Cassandane's corona wrapped around Sam and lifted both of them up their apartment. "I want you to dedicate some time before sleep each night attempting to clear."

"Yes, Professor McGonagall."

"I don't understand your cultural allusions, Sam."

"You're probably not missing out on much. My friend Jess is the only one who ever thought I was funny. I wish we could break her out of mind control slavery."

Cassandane shook her head. "The executives would not tolerate a second naturalization."

"Well, if you ever go berserk, be sure to jail break my friends at the farm. It would be Rambo meets Moses meets Yoda."

"I don't know those three people."

"One was a crazy skilled soldier, another freed some slaves, and the third is a little green alien with space powers. Or maybe a better mashup would be Sarah Connor meets Ellen Ripley meets Wonder Woman. That's a woman fighting time traveling robots to save the future, a woman killing aliens that lay eggs inside people, and a female Superman."

"Sam," Cassandane said, "I'm not able to replace your friend. Truthfully, I wouldn't want to even if I could."

"Uh, okay . . . ."

"What I can do is instruct you in the talents better than anyone else in this solar system. Practice clearing, Sam."