Jānussoni, travelling in a carriage, meets Pilotika, from whom he hears praise of the Buddha. He learns how Pilotika, having heard the Buddha's teachings to nobles, Brahmins, house-holders and recluses, was convinced that the Buddha was all-enlightened, just as an expert elephant-tracker seeing a broad elephant-footprint would conclude that it indicated the track of a really large elephant.
Jānussoni goes to visit the Buddha and reports his conversation with Pilotika. The Buddha tells him it would be a mistake to conclude at once from seeing a broad footprint that it belonged to a very large elephant; there are many other possibilities which should first be eliminated. He then proceeds to describe the life of a real recluse, the disciple of the Noble One, and the attainments he reaches; these he calls the Truth-finder's foot prints. Following this, the disciple makes further discoveries, till his mind is completely free from the āsavas, and then he realises the Truth-finder's real quest. Jānussoni becomes a follower of the Buddha (M.i.175ff).
This was the first sutta preached in Ceylon by Mahinda to Devānampiyatissa. At the end of the discourse the king accepts the Three Refuges. Mhv.xiv.22.