Finding model created using ArcGIS ModelBuilder?

I made a model in the ModelBuilder (arcgis 10.2) and saved it. Unfortunately, not some place where I can find it again.

However, if I want to save a new model (save as..),the old model is there in toolbox.tbx.

Does anyone know how I can re-open my model again? ArcCatalog is not helping me so far.