We introduce a fully-abstract intensional model for a polymorphic call-by-value language with higher-order references. As in game semantics, the denotation of a term is represented as a set of plays between the term and its environment. But rather than building it compositionally, by induction over the term, we generate it using a labelled transition system representing all the possible interactions between the term and any environment. Names, and more generally the theory of nominal sets, are crucially used to represent locations (i.e. memory addresses) and functional and polymorphic values. Freshness of such names then control the observational power of environments. Thanks to the presence of references, the observational power of environments is strong enough to avoid the need of performing a quotient of the model to be fully abstract. This gives us new principles to reason on effectul and polymorphic programs. This work has been done in collaboration with Nikos Tzevelekos (QMUL).