RPG Character Chatbot for Website

Working on a videogame and want to set up several plot-driven chatbots from the perspective of characters involved in specific scenarios.

Looking to set up a chatbot that would guide a player through pre-determined story in messaging format. To enable world introduction and immersion, we want to set up chatbots in the style of "solo text RPGs", with characters actively engaging players to drive the storyline. We have scripts for several stories, featuring original characters, and are looking to set up chatbots that would allow these characters to proactively message the player and guide through the pre-determined plot, reaching a specific conclusion.

Let's say a character is a player's roommate who forgot a book at home in a different town. The character proactively messages the player with descriptions of how to find a book and bring it to them. While on the way to the town, the player encounters more adventures according to the storyline, which they discuss over chat. Once the player "completes" his mission, the chat ends.