When Diamond Tiara asks her dad about summer jobs, she doesn't expect him to refer her to somepony else--and she really doesn't expect that somepony else to be a mare she's never met with a personality as dull as her coloring. As it turns out, however, much like the things she studies, Maud may be far more complex than her exterior suggests.
(Set a year or two post-Ending of the End, though technically there's nothing that grounds it in any particular time frame past Diamond's reformation.)