We investigate an example of flare having the shape of a long, bright filament in soft X-rays (SXR). Another characteristic feature of the flare and of other similar flares is that a few emission kernels, best seen in hard X-rays (HXR), develop along the filament. The kernels are new sites of the flare energy release. It is shown that the kernels develop at the crossings of perpendicular magnetic flux tubes. The flare energy release, and the flow of heat and plasma along the filament are carefully investigated.