She later initiates a neurosurgical clinical trial, enlisting Derek as a consulting neurosurgeon. The trial fails repeatedly, but the final patient they treat survives, which leads them to reuniting and moving in together. Their relationship is healthier than before, but still experiences snags as the two attempt to understand each other and navigate what they now look on as a permanent, long-term relationship. Meredith relies heavily on Cristina for emotional support and guidance. Eventually, Derek and Meredith decide to marry, but on their wedding day, the pair give their "perfect" wedding ceremony to Izzie and Alex, to marry each other during the planned ceremony instead.