>>95880322
That's good advice. In this situation, tho, it's a little harder, since they're ignoring the other stuff in order to follow what they think is their target.
Maybe a combat encounter out of the blue is the best option. It will make them angry at the attackers and want to get involved.

>>95881172
Well, you tell me.
>the monk guy was explicitly said to be part of a cult
>one of the pcs knows a guy from that cult
>they sent a spy to gather information on that very same cult many sessions back
>spy found the monk guy, and I made a point to say he did so by investigating the cult
>spy got his leg irreparably destroyed by the monk, and managed to get away by throwing himself into the sea. Since then, the monk got another hideout
>they know where the cult is located, they're open to the public and the players have a contact ove there
The obvious choice in my mind is investigating the cult.