Ok so rewatching a gameplay of Call of Cathulhu Dark corners, and having reread some one Mythos based threads I am in a Mythos Mood as you do.
While I don't have a 'Plot' in mind I do have a starting point and a Character, one who might stir things up in little old Innsmouth
Hope is an eager young woman with a passion for history and stories. Why? Because she's an Empath, she can sense strong feelings, see old memories, and even read mind of people who aren't very well shielded.
Her favorite thing is to explore old towns, buildings, land, and see what memories she can read, correlating what she's seen with paper work to write books and correct historical recordings if needed.
In her research she'd learned of an isolated town, Innsmouth. A place that prefers to keep to it's self and has a very old world feel she was told of this place by a man looking for a family friend. As Hopes Empathetic abilities has been used in police work the man hopes she might be able to find out what happened to the boy. Wanting to help, and loving the idea of visiting a town with so many historical remnants Hope agrees to the job.
After a long train ride she's arrived in Arkham and about to Board a Bus that will take her to the little seaside town.. but.. what happens when she gets there? That's up to you.