In this paper we apply the L-function Ratios Conjecture to compute the one-level density for a symplectic family of L-functions attached to Hecke characters of infinite order. When the support of the Fourier transform of the corresponding test function f reaches 1, we observe a transition in the main term, as well as in the lower order term. Assuming GRH, we then directly calculate main and lower order terms for test functions f such that supp( f) ⊂ (−1, 1), and observe that the result is in agreement with the prediction provided by the Ratios Conjecture. As a corollary, we deduce that, under GRH, at least 75% of these L-functions do not vanish at the central point.