The Eugenia (or Ocean Tramp Tankers Corp v V/O Sovfracht) [1964] 2 QB 226 is an English contract law case, concerning the frustration of an agreement.

The Suez Canal became a "dangerous zone" as The Eugenia, carrying iron and steel, sailed towards it on the way to India from Odessa (but starting in Genoa).

The charterers, in breach of a "general war clause" in the contract saying dangerous zones should be avoided, sailed into Port Said, thinking they could make it through the canal in time.

It is simply this: If it should happen, in the course of carrying out a contract, that a fundamentally different situation arises for which the parties made no provision – so much so that it would not be just in the new situation to hold them bound to its terms – then the contract is at an end ... the theory of an implied term has now been discarded by everyone, or nearly everyone, for the simple reason that it does not represent the truth.

But if the contract says nothing, onerous or more expensive is not enough; "It must be positively unjust to hold the parties bound.