With an aim to investigate the nature of Mandarin neutral tone through the lens of language variation and change, this study examines the pitch patterns of speech sequences containing neutral tone syllables, i.e. those do not have any of the four canonical lexical tones and often overlooked in prior studies of tones, in two Mandarin varieties: Standard Mandarin and Plastic Mandarin spoken in Changsha, China. Using Generalised Additive Mixed Models, the study shows (a) that f0 contours of a sequence of neutral tone syllables following various lexical tones converge in the end at a low pitch in both Mandarin varieties, and (b) that the low pitch target of neutral tone syllables tends to be the same across the two Mandarin varieties. The cross- dialectal comparison favours the phonological account that neutral tone is underlyingly underspecified and attracts the boundary tone and suggests that the constant pitch target across two Mandarin varieties with different lexical tone contours may be attributed to the stable transfer of prosodic structure in the Standard-Plastic variation.