Legal Principle: Where both parties to an agreement are under a mistake as to matter of fact essential to the agreement, the agreement is void. Factual Situation: A agrees to sell to B a specific cargo of goods supposed to be on its way from England to Bombay. It turns out that before the day of the bargain, the ship carrying the cargo had been cast away and the goods lost. Neither party was aware of the facts. Issue: What is the nature of contract? Decision: