Boss Danzo's first order upon returning from his meeting with Tsunade is to Sai: pick a ninja, any ninja of high rank and skill in Konoha, and observe them for a few days. The object: to learn some kind of skill that could become useful in making ANBU a stronger organization. He called Sai into his office to give him the orders, making sure to take the picture of the Third Hokage off the wall, covered in markings and tiny holes from a series of multiple frustrated stabs of his kunai.
". . . and that is your mission for this week," Danzo grumbled from behind his desk.
Sai blinked. "Sir, I remember a fortnight ago you said that the current state of ninja of Konoha were horrible, wine-drenched louses better served to lick the desert clean of dirt until the end of time."
"Just do it, you idiot!" Danzo roared, nearly knocking over the desk as he stood, red-faced.
So, after a moment spent studying the files in ANBU's database, he chose the file labeled "Jiraiya". The absence of a family name duly registered, as did the fact that said file hadn't been updated in several months (which might have been due to the fact that ANBU's old data maintainer was recently turned into human shrapnel after accidentally setting off an explosive tag in his sleep). After a good hour of studying Jiraiya's file and realizing that he would have to follow around the Legendary Sannin -- the Toad Hermit who fought alongside Orochimaru and the Fourth Hokage in his youth, the man even Itachi Uchiha was afraid of fighting -- for a week, he packed up his essentials in his fannypack and set out to find the Legendary Sannin in his natural habitat.
Sai's first lesson: It's hard to take the Legendary Sannin seriously when he's drunkenly peeking into ladies' bath houses. Especially when said ladies came out of the bath houses, faces flushed with anger, throwing kunai and chairs and whatever they could get their hands on at a swiftly retreating (and giggling) old man.
It could be worse, Sai reminded himself. He could be following around Team Gai's very own leader, running around in leg warmers and spandex. The very thought sent a cold shudder through his body.
The second day, Sai found himself rummaging round in his disguise box before discreetly following Jiraiya into the ramen bar. He wondered why the Great Sannin would come to such a place at eleven in the morning --- then watched as the first thing Jiraiya ordered was a bowl of a ramen, followed by two drinks. And they weren't water, either. Perhaps Jiraiya would be too intoxicated to notice the androgynous woman with the fake-looking hair and too-bright make-up by the end of the bar, watching him from behind his -- er, her paper fan as "she" sipped iced tea through a straw. Certainly such a woman as himself would not attract the attentions of such a ninja, who seemed too busy with his warm sake and ramen bowls to pay him any mind. Or not.
Sai remembered too late what one of Sai's great weaknesses in life was only hours later as, still in disguise as "Satoko" (his code name, thought up in a second), he found himself carrying a drunken Jiraiya back to his apartment, the weight of the ninja straining the muscles in his arms and legs to their upmost limits. Before then, the man had spent the evening chatting "Satoko" up, telling the naive girl about his exploits as a great ninja; even Sai, in his ill-fitting wig and girlish kimono, could not help but be impressed just a little bit by his stories, even if half of them seemed rather exaggerated. He nursed a single tall glass of iced tea the whole night while Jiraiya killed off bottle after bottle of alcohol, the liquid permeating his breath until every word he spoke was like one big boozy exhale.
As they reached the threshold that led into the older man's apartment, he heard the sannin rumble in a drunken whisper, "Satoko-san, let's get married," before pushing his drunken red face into Sai's own ghost-white face.
The younger man's scream of terror could be heard from the walls of Konoha; a feminine-like shriek which was suddenly silenced, as if the mouth screaming had been cut off by another's. The guards just glanced at each other and chuckled, short thoughts on young lovers flitting briefly through their minds.
Sai returned to Danzou's office a week later, as stoic-faced as ever and possessing all his limbs intact, which for him was a record achievement.
Danzou barely registered Sai's presence, so intent was he in scratching out characters onto a sheaf of papers on his desk. "Do you have your report on Jiraiya ready for me?"
"No."
The quill in his hand faltered for a second, the harsh tch reverbrating through the air like a knife. "Why not? I have given you ample time to do so. What possible excuse could you have ---" He noticed an odd glint coming off of Sai's hand and finally lifted his head to see it clearly.
Sai held up the offending hand. "I am now married," he said as easily as one declares being sleepy or hungry. He would later wonder why his master had fallen to the ground in a dead slump, unconscious. The teen shrugged and left the office to summon a medic nin, all the while wondering what Jiraiya would be wanting for dinner that night. After all, that was one of his duties as his wife "Satoko", was it not?
Now, the idea of consumating their marriage -- well, that was a bridge Sai would have to cross when he came to it. He wondered if Danzou would want the details of their intercourse in his report. Of course he would, Sai thought cheerfully. It was always good to have a complete report of his activities for his master to read. And he did mean complete.