If your a player whose adventure is starting on the island of Nabban stop reading!

So I’ve been scouring some other “how do I start a campaign” or “how do I frame my players” threads but need specific help. For framing the big consensus is make sure they have some agency and don’t feel railroaded.

My campaign start is in the works: My players (5) are all mostly from different places. Two are siblings, two are friends, the fifth is a loaner. In our session zero we decided all the players are united by questing after a secret arcane society to further their magic. For reference, magic has just returned to the world.

My idea currently is they don’t know each other yet and instead meet for the first time by following a mysterious invitation they each individually received to a tavern. They have all received mysterious letters (or maybe visions, dreams) from a man instructing them to come to a specific tavern. They all meet at the tavern, meet the mysterious contact, begin talking about how he is part of this secret society and why he asked them all there, and suddenly a magical assassin teleports into the room via dimension door or something, murders their contact, and immediately vanishes. How much they learn exactly from the contact and how much clues as to who his assassin is I haven’t determined yet.

My goal: To inspire the players to use what they learned to take the next step in locating the secret society and to be driven to solve who (or really what group) murdered their contact by having been witness to it and getting their info cut short.

My question: Is it necessary to frame the players for murder to motivate them to solve the identity of the assassin? Should I save it in case they are not motivated (to chase them up a tree as Matt Colville says)?

What ideas do you all have? Improvements? This is my first home brew campaign so any help is appreciated!