The battle lines are drawn for the Destiny War. The 3 Time-Keepers and Immortus want to wipe out most timelines containing humanity. Rick Jones, Kang, the Kree Supreme Intelligence and 7 Avengers plucked from various times want to stop them. Kang also wants to avoid turning into Immortus. No-one really knows the Kree Supremor's motive. Meanwhile Libra, earlier an ally on the Avengers side, is watching the proceedings in the interest of Cosmic Balance.
Libra unconvincingly guesses why the Cosmic Balance made him guide Rick Jones into picking these particular 7 Avengers.
Rick Jones, Kang and the Supremor are riding a souped-up dune buggy. Rick is driving, Kang is shooting, and Supremor acts as an on-board computer.
Time-Keepers and Immortus retreat to the Citadel at the End of Time, where the Time-Keepers were born. Yellowjacket uses Limbo insects to lead his side after them.
Time-Keepers want Immortus's Forever Crystal, generated from the collapse of Chronopolis in #3, to power a chrono-cannon to destroy the relevant timelines in one go. Immortus gets cold feet, because he has always protected the Avengers and humanity by toning down the worst the Time-Keepers wanted to do. So they kill him.
To protect themselves while the chrono-cannon warms up, Time-Keepers bring in various evil versions of Avengers. Libra decides to get off the fence, and reactivates Rick Jones's Destiny Force. It spreads to the 7 good Avengers, except Captain Marvel who isn't human, enabling them to fight against superior odds.
Time-Keepers turn Libra into a weapon to ramp up Rick Jones's Destiny Force. It freezes most of the combatants, as it did to end the Kree-Skrull War.
Kang is left to face Time-Keepers alone. They try to force him to become Immortus.
Captain Marvel's non-humanity enables him to fight the Destiny Force freeze, enough to clash his Nega-Bands together. Amazingly this swaps him for an older version of Rick Jones, with a beard, a scarred face, a missing arm and the Nega-Bands (one of them hanging from his belt), and wearing the Eye of Agamotto, Falcon's boots, and what looks like Batman's utility belt and the remains of Superman's cape.
Old Rick says he and young Rick can't access Destiny Force alone, but together they might. They materialise a horde of good Avengers from various timelines.