Sarglaoxolane A (1), the first lindenane-normonoterpene heterodimer fused by tetrahydrofuran, was discovered in Sarcandra glabra guided by the first proposed single-node-based molecular networking approach. Moreover, two pseudonatural derivatives (2 and 3) with an oxa-difuranofurone moiety were transformed from 1 and confirmed by X-ray diffraction, and also proven to exist in the plant extract. A combination of molecular networking and biomimetic transformation can significantly promote the discovery and structural elucidation of novel natural products.