?」「

'Huh? Where's Keiko?' 'She says she'll be late because she has a three-way meeting today.'

Literal

''Huh? Keiko [topic-は]?'' ''Today [topic-は] three-party-meeting is-[because-から] late-become [quotative-って]''

Mundane school logistics. 三者面談 ('three-party meeting') is the standard term for the parent-teacher-student conference common in Japanese schools, where the student, parent, and homeroom teacher discuss the student's progress and future plans. ~って at the end quotes what Keiko said. 遅れる ('to be late') is the standard verb for being delayed.