Overview of the filament in a nest of three active regions. The northern filament (Nfil) does not evolve while the southern filament (Sfil) erupts, i.e., mainly its eastern part, which is marked with cyan contours in all the panels. The images were obtained by SDO/HMI, SDO/AIA, GONG, SUTRI, and STEREO/EUVI-A on 2022 October 4 before eruption. The filament is visible from the chromosphere to the transition region and the corona as a dark channel. The magnetogram shows that the filament lies in a mixed-polarity area between AR 13115 and AR 13114 (panel a) and extends along 350 arcsec in longitude (panel b).