The initial round for college recruiting, after you've passed the resume screening process, consists of a one-on-one interview with a young staff member (when possible, they do it from your school, which I've learned is because alumni have a better sense for the overall applicant pool from that school and how a given individual fits in). This is largely a behavioral interview, but they're also trying to get a feel for the kind of work you're interested in and your skills set. They're doing this to figure out which of the teams/market areas within Booz you would/wouldn't be a good fit for.
The next round consists of a career-fair style round-robin session with all the undergrad/grad applicants from a couple of core target schools. This is a chance for the applicants to meet and greet with all the teams who are currently looking for young go-getters. You spend about 15 minutes with all the teams that you're interested in. Make sure you bring extra copies of your resume, as some of the teams you've initially selected won't remember to print them off or you may find some new ones you didn't even know about.
Then after the rounds of interviews are done (there are a couple hours of this), you mark down which teams/groups you were most interested in after the interview and the team/group representatives do the same for their preferred applicants. Where there are matches, you have a possible hire.