Subjunctive in Spanish
Also the expression of need requires the subjunctive mood in subordinate by the same reason we mentioned in the last point of Subjunctive mood: wish http://www.spanishonlineresources.com/sentences-that-expresses-wish-deseo-subjunctive/
The need is a form of craving realization of the wish that takes on added importance in the case of an expression of simple desire (I want, I want …).
Necesito que me digas que paso. I want you to tell me what Happened.
Necesitamos tu ayuda. It doesn’t have the structure (VERBO + QUE + SUBJUNTIVO)