The Librarians - a mystery by Sherry Thomas

When Hazel Lee moved back to Austin after years in Singapore, her grandmother suggested she get a job at the library and she finds one at her own childhood branch. Hazel is welcomed by Astrid, one of the librarians; Sophie, the branch administrator; Jonathan, the program director; and several clerks. They think Hazel is elegant and slightly mysterious but have no problem with her work ethic: