Case of the Pilfered Proof [Murders at Karlov Manor]

Introduction

Whenever a Detective enters the battlefield under your control and whenever a Detective you control is turned face up, put a +1/+1 counter on it.

To solve You control three or more Detectives. (If unsolved, solve at the beginning of your end step.)

Solved If one or more tokens would be created under your control, those tokens plus a Clue token are created instead. (It’s an artifact with “2, Sacrifice this artifact: Draw a card.)