Optimal Situation is the fortieth episode of the Beast Wars TV series.
As a time storm ravages reality, Megatron gloats to the fading Maximals, since his attack on Optimus Prime ensures that the Autobots lose to the Decepticons, resulting in the Predacons having control of Cybertron. However, Blackarachnia, having been a Maximal protoform, is also affected by the time storm. She uses the information from the Golden Disk to activate Teletraan I's security system, forcing Megatron out of the Ark.
Blackarachnia and Silverbolt activate the Ark's repair systems to help stabilize Optimus Prime's condition, but the Autobot leader is still dying, and "reality is still in flux". The other Maximals arrive, and upon seeing Prime, realize that they must save him. However, his spark is fading. Believing there is no other choice, Optimus Primal merges his spark with Prime's to save it. He succeeds, and Rhinox summons an Autobot repair device to begin restoring Prime's body. Holding Prime's spark causes Primal to expand into a new, larger body.
Megatron and Inferno arrive and attack, though Primal manages to save the Maximals and convince the Predacons to leave, while Blackarachnia uses the commotion to escape. Outside, Waspinator provides cover fire by shooting the rocks above the Ark. The Predacons destroy the cave entrance and flee, but Megatron notices a trapped Blackarachnia. Enraged by her betrayal, Megatron shoots her as the Maximals break free. Knowing that they are heading for the unprotected Axalon, Primal and Cheetor race off.
As Silverbolt cradles the damaged Blackarachnia, he begs her to fight on and praises her defiance of Megatron. She maintains that what she did was self-preservation, but Silverbolt points out that she also saved him and the universe. He openly admits to Blackarachnia that he loves her, shocking her. While there's still time, Silverbolt asks her one last time to join the Maximals. Although she maintains that she's still a Predacon, Blackarachnia joins the Maximals for him, then goes off-line. However, Rhinox reveals that she's merely in stasis lock.
Primal and Cheetor manage to down Megatron, Inferno, and Waspinator, but Primal discovers that Rampage and the Arachnoids are literally trying to drag the base away. Optimus manages to sever the lines and dispatch Rampage, but not before Rampage fires a missile which deflects off Primal and hits the Axalon. The Axalon plummets off the cliff and crashes into the river. Knowing that he must return Prime's spark, Optimus withdraws with Cheetor to rejoin the Maximals.
Back in the Ark, the repairs are finished. Returning the spark causes Optimus Prime to reactivate briefly, but he almost immediately returns to stasis lock. Rattrap is less than happy, as they now have the difficult task of protecting the Ark from the Predacons. With the time stream safe—for the moment—Optimus orders the Maximals, including Blackarachnia (who still maintains she's a Predacon), to begin rounding up every piece of salvage and make fortifications.
They're moving into Mount St. Hilary.