Why one character holds many storylines
A storyline is a separate scene: its own title, opening, and chat. The character stays the same person.
The character page is a shelf
A single chat card collapses every mood into one thread. Plotty splits them. The character page lists storylines the way a shelf lists books: a café meeting, a storm, a slow mystery. Each ticket has its own summary.
Chats are kept apart by the storyline, so starting a second scene does not erase the first. You come back to the shelf when you want a different room.
What should change between storylines
Change the place, the stake, and the opening. Keep the name, the voice, and the relationships that define the person. If two storylines could swap their first messages without anyone noticing, they are the same scene written twice.
The public summary is the line under the title. Write who is there, where they are, and what is unresolved. That sentence is what the shelf, search, and the chat preview share.
How to pick one
Open the character, read the storyline titles, and enter the scene whose summary matches the hour you actually have. A short evening can be one meeting. A longer sitting can be the storyline that already has a cast waiting.