If the plaintiff wants a court order that requires the defendant to fulfill the terms of the contract, the plaintiff is seeking .

A court Injunction

Explanation:

A plaintiff is someone who institutes or starts a legal case against another person in a court of law.

A defendant is the person who has been summoned to a court of law to answer to a case instituted by a plaintiff.

An Injunction is a court order that compels a person to carry out or refrain from carrying out a specific action.

So in this question, if an agreement or a contract exists between two people and one of them does not want to fulfil his/her part of the agreement, then the aggrieved person (plaintiff) can go to a court of law to obtain an injunction that will compel the erring person (defendant) to fulfil his/her part of the contract,

a court injunction

Explanation: The plaintiff is seeking a court injunction which is defined as a writ (written order, issued by a court, ordering someone to do (or stop doing) something) or process, granted by a court of equity, and, in some cases, under statutes, by a court of law, whereby a party is required to do or to refrain from doing certain acts, according to the exigency of the writ. If the defendant in this instance fails to comply with the injunction, s/he faces criminal or civil penalties, sanctions or even imprisonment, in addition to being charged with contempt of court.