Rachel was, of course, the one who came up with the idea. She would tell anyone who asked, as well as telling Finn repeatedly even when he didn't ask, that this was because of her keen observational skills and altruistic nature. Even Finn thought that that sounded a little off, but he figured her intentions were good, so he didn't say anything. But regardless of why, the end result was Rachel sending out a mass text calling an emergency Glee meeting to discuss having an intervention for Blaine's problem. What the text didn't specify was that Blaine was not to be at this meeting, which Brittany thought was confusing, Santana thought was aggravating, and Artie (privately, in line with his new safety plan of not doing anything to remind Santana that he and Brittany used to date) thought was stupid. Luckily, Santana managed to successfully avert that catastrophe and the rest of the Glee Club made it to the choir room without incident.
Once they were all gathered Rachel laid out what exactly she thought Blaine's problem was (which the text also hadn't specified) and what she thought they ought to do about it. Kurt found himself enthusiastically agreeing with her, as this particular problem was one he tried to bring up twice before. The first time with Blaine, who, in the grand tradition of anyone with an addiction, denied any such addiction existed and insisted he could "stop whenever he wanted." The second time was with the rest of the Warblers, who were all way to lost in their collective man crush on Blaine to admit that he might even have something tangentially related to something slightly resembling a problem. Mercedes also agreed to the intervention on the principle that if Blaine's boyfriend thought there was a problem then there probably was. Finn went along with it, mostly because he generally felt he had to go along with anything that both his girlfriend and his stepbrother agreed on, unless he wanted his life to be a living hell at least the next week or so. Sam found himself torn between the fact that he wasn't really sure that what Rachel was describing was actually an addiction, not to mention he still didn't like that Blaine guy all that much, and the fact that he really wanted to date Mercedes again. Quinn offered that they should all be there to help their friends when they needed it, but declined to elaborate as to whether she actually thought Blaine needed it. Artie, Mike, and Tina all seemed to understand where Rachel was coming from, but didn't think an intervention was really necessary. Puck and Santana were less than impressed by the whole thing, and Brittany agreed with Santana by default, since she had stopped paying attention half-way through in favor of planning her own intervention with Ken, Barbie, and Santana in yet another attempt to get Lord Tubbington to quit smoking. Rory didn't voice any opinion at all, nor did Brad, who had wandered in on the off-(read, extremely likely) chance that Rachel would need to sing to get her point across.
Santana, now sure that there weren't enough members in favor of Rachel's latest crazy scheme to force her to go along with it, got up and left, Brittany in tow. The two girls were followed out by all the others who thought this whole thing was a waste of time, including Quinn and Rory, or so they surmised by his absence once the room cleared. It would later turn out that Rory wasn't there because Rachel had failed to get his number when he first joined New Directions, or on any other occasion since then, and so he hadn't been invited to the Intervention Planning Meeting in the first place. Which was too bad, as Rory had an uncle who had had a very similar problem, and likely could have helped. But regardless of why, the fact remained that the only people left in the room were Rachel, Kurt, Mercedes, Finn, Sam, and Brad, who, despite not saying anything, was genuinely concerned.
Mercedes suggested that they have an intervention with just them, which Kurt shot down in favor of at least attempting to convince the other kids that Blaine had a serious problem that they all needed to help him with. Agreed, the five students began to come up with a plan that could only possibly work because it was just that ridiculous and ill-advised. Meanwhile Brad began compiling a list of all of the upbeat Top 40 songs he had sheet music for, thus enacting Phase One of his plan to get the Glee members to throw Blaine an intervention. A plan that was both twice as sensible and ten times as likely to work as anything the kids might come up with.
Five school days and fourteen impromptu musical numbers later, Santana stalked up to Rachel and slammed her locker door shut.
"Alright Berry, throw this intervention thing or whatever, 'cause I cannot takes one more second of the Hobbit's special brand of crazy."
"While I thank you for your support Santana," Rachel responded, "we still need the entire Glee club if we really want to get through to Blaine."
"You let me worry about getting everyone there. You just make sure that this stupid intervention thing works." And with that Santana pulled out her phone and began calling the other members of New Directions, most of who were standing within ten feet of her at the time, to let them know that they were doing this thing after all.
The following Monday Blaine walked into the choir room to find that the entirety of the Glee club was already there, including Rory, who had overheard Brittany and Santana talking about the upcoming intervention for Blaine after the highly successful intervention for Lord Tubbington (two days clean!) on Friday afternoon, Brad, who was looking smug about the success of his plan, and Will, who was trying to figure out when Blaine had gotten into drugs since no one had told him anything other than "we're going to help Blaine with his addiction." Sugar was also there, much to everyone's confusion, since no one had seen her in over week and they all thought she had quit or something.
Everyone could tell the moment Blaine realized there was no furniture in the room because he started trembling and inching toward the piano, which had to be left were it was because it was too big for any of them to figure out how they were supposed to fit it through the door.
"Blaine, honey," said Kurt as he crossed the room and placed a comforting hand on his boyfriend's shoulder. "It's going to be alright; we're all here because we care about you."
"Kurt… guys, what's going on?"
Rachel, who felt it was her responsibility to take charge as both co-captain of the Glee club and the originator of this idea, approached Blaine, being sure to maintain eye contact, and took his hand in order to establish a physical connection. "All of us are here today because we're concerned about this serious addiction you have. You, Blaine Anderson, have a compulsive need to jump on furniture."