We consider the Grassmannian X = Gr n−k (C n ) and describe a 'mirror dual' Landau-Ginzburg model (X • , Wq :X • → C), whereX • is the complement of a particular anti-canonical divisor in a Langlands dual GrassmannianX, and we express W succinctly in terms of Plücker coordinates. First of all, we show this Landau-Ginzburg model to be isomorphic to the one proposed by the second author in [73]. Secondly we show it to be a partial compactification of the Landau-Ginzburg model defined earlier by Eguchi, Hori, and Xiong. Finally we construct inside the Gauss-Manin system associated to Wq a free submodule which recovers the trivial vector bundle with small Dubrovin connection defined out of Gromov-Witten invariants of X. We also prove a T -equivariant version of this isomorphism of connections. We conjecture that the free submodule above is isomorphic to the entire Gauss-Manin system (a tameness property for Wq). Our results imply a special case of [73, Conjecture 8.1]. They also imply [6, Conjecture 5.2.3] and resolve [67, Problem 13].