Tropic movement in plants (movement in relation to a directional stimulus) has fascinated thinkers since ancient times (for review, see Whippo and Hangarter, 2006). This interest has led us to a good molecular understanding of how, for example, plants direct their shoots toward light and their roots toward water. However, this is not the only form of movement in plants. Nastic movements occur in response to nondirectional environmental stimuli such as temperature. Warm temperatures promote the raising of leaves in several species (a process termed thermonasty). In comparison with tropic movements, nastic movement in plants is poorly understood. In this issue of Plant Physiology, Park et al. (2019) use an exceptionally broad range of techniques to provide a deep mechanistic insight into how thermonasty occurs in Arabidopsis (Arabidopsis thaliana).