Hypothesis is a tentative interpretation/explanation of observations. A good hypothsis can be either confirmed or refuted by further observations, such as by controlled experiments and procedures.
Law is a brief statement that is a summary of previous observations, and prediction of future ones. For example, there are Laws of conservation of mass, which states that "matter can be neither created nor destroyed." Laws are indisputable oversvations.
Theory is a model for the way nature is and attempts to explain why nature is the way it is. Theories are validated by experiments, and as long has to there is no evidence to dispute it a theory remains valid. A theory is essentially a summary of hypotheis that have repeated been valid.