The Saddest Death In Criminal Minds Season 8
Prior to "Zugzwang," the season introduced a love interest for Spencer Reid (Matthew Gray Gubler). After the onset of frequent and debilitating headaches in Season 6, Reid eventually connected with geneticist Maeve Donovan (Beth Riesgraf). The two exchange frequent phone calls, as seen in Season 8, Episode 4, "God Complex." During one of their chats, Reid suggests that the two meet in person, but Maeve nixes the idea. She's concerned that her stalker — who has driven Maeve to extreme seclusion in her home — might target Reid.
A few episodes later, in "The Lesson," Reid and Maeve come to believe that her stalker has ended their obsession. With the threat presumably over, the two agree to meet at a restaurant. Unfortunately, Reid mistakenly thinks a man at the restaurant is Maeve's stalker. In a panic, Reid calls her, warning her away from the restaurant and postponing their long-overdue meeting. Though they delayed their date, Maeve has a book delivered to Reid in which she's highlighted certain text that expresses her love for him.