The two groups dispute who shall go first to heaven. The Angirases 'see' a pressing for the morrow and send Agni, himself an Angiras, to announce it. The Adityas see a same-day pressing and claim Agni as Hotri; he agrees and tells the angry Angirases that to refuse one who comes with the priestly function is to refuse fame. The Angirases sacrifice for the Adityas. As fee they are given the earth; accepted, it burns them; cast away, it becomes a lioness with gaping jaws and attacks men, and the fissures in the ground date from this. Hence a laid-aside gift is not to be accepted. Then the sun in the form of a white horse with a halter is brought and accepted; the Devanitha verses recall it. A sacrifice without a fee is like a cart without a leader. AB 4.17 adds that the Adityas reached heaven first and the Angirases sixty years after.
The Angirases prepare a sacrifice and send Agni to bid the Adityas minister at it tomorrow. The Adityas decide only another sacrifice can get them out of this and hold a Soma feast the same day, with Agni as Hotri; another messenger is sent back. The Angirases reproach Agni, who says the blameless chose him. They officiate with Soma bought the same day (the Sadyahkri). The fee first brought is Vac; they refuse her as a loss, and the rite stays incomplete until Surya is brought and accepted, hence the white horse with a gold ornament as fee. Vac, angry at being refused, becomes a lioness roaming between gods and Asuras; both call her; she goes over to the gods on the promise that the offering shall reach her before Agni. The high altar is Vac.
What is different here:
The first fee is Speech, refused outright, not the earth accepted and thrown away; it is Vac, not the earth, who becomes the lioness; the story continues with the gods winning her over; nothing about fissures or about who reached heaven first.
A short form: the Angirases send Agni to ask the Adityas to sacrifice for them tomorrow; the Adityas answer that their pressing is today, with Agni as Hotri, Brihaspati as Brahman, Ayasya as Udgatri and Ghora Angirasa as Adhvaryu. A white horse, the one who gives heat, is the fee. 'Therefore the Adityas went to heaven.'
Sources: Rigveda Brahmanas: the Aitareya and Kausitaki Brahmanas, tr. A. B. Keith (1920); The Satapatha-Brahmana, tr. Julius Eggeling (Sacred Books of the East 12, 41)