What is toxic, how does bioaccumulation and biomagnification work, how do toxins influence Arctic ecosystems? How is toxicity studied and calculated? Is it safe to eat fish? What to “mad hatters” have in common with dancing cats? How do toxins reach the Arctic, what is “grasshopper effect”? What is the name of the most mercury-polluted predator in the Arctic? Is it possible to receive a Nobel prize for discovering a dangerous poison?