Plan reconstruction is a task that appears in plan recognition and learning by practice. The document introduces a method of building a goal graph, which holds a reconstructed plan structure, based on analysis of data provided by observation of an agent. The approach is STRIPS-free and uses only a little knowledge about an environment. The process is automatic, thus, it does not require manual annotation of observations. The paper provides details of the developed algorithm. In the experimental study properties of a goal graph were evaluated. Possible application areas of the method are described.