In 1882-4, Frances Groome's Ordnance Gazetteer of Scotland described Plean like this:
Plean, a village and a quoad sacra parish in St Ninians parish, Stirlingshire. The village, lying 3 miles SSE of Bannockburn, has a post office under Stirling, a public school, and an asylum or hospital for 30 old men, founded by Col. Francis Simpson, who died in 1831. Plean House is in the western vicinity of the village. The quoad sacra parish, constituted in 1878, is in the presbytery of Stirling and the synod of Perth and Stirling; the living is worth £289. Pop. (1881) of village, 369; of q. s. parish, 1037.Ord. Sur., sh. 39, 1869.
GB Historical GIS / University of Portsmouth, History of Plean, in Stirling and Stirlingshire | Map and description, A Vision of Britain through Time.
Date accessed: 30th March 2017
Click here for more detailed advice on finding places within A Vision of Britain through Time , and maybe some references to other places called " Plean ".