Night Wanderer (夜旅人) is adapted from the novel written by Zhao Xi Zhi and has confirmed the leading couple in Ni Ni and Deng Lun with their released posters. The novel follows two individuals – our heroine is from the year 2015 and she’s famous female forensic doctor, returning home from a murder scene and witnessing the corridor lights flicker. On the same night but in 1937, our hero – a lawyer in Shanghai also returns home when the lights go out. The time and space of these two people are connected by a lamp. He’s described as gentle, old-fashioned, and righteous, while she’s described as cool, calm, and courageous. The first time they meet, he’s in no hurry as he helps her to the hospital with a black umbrella. The second time they meet, he has become her tenant, holding a tenant contract from 1937. Lol. Their love transcends time and space, and once it explodes, it’s eternal.
That is the novel excerpt, but when I checked the drama synopsis on baidu, it sounds different. This may be another case where some plots/descriptions are changed to accommodate drama making.