The opening episode of the third season kicks off with the introduction of 7 new eclectic cast members who make up the Sparrow Academy crew, a doppelganger group of the original members of the Umbrella Academy. A brawl breaks out, and the Sparrows are winning before Vanya overpowers them using her powers. The Umbrella Academy members retreat to a hotel and are disappointed in Reginald's decision to adopt the Sparrows.
The members of the Umbrella Academy know that the Sparrows will most likely come looking for them to fight them, and the only way they could be safe is if they had their time-traveling briefcase to get them out of that timeline. A man named Lester packs sandwiches to flee his cabin in the woods and is later seen listening to a cassette while onboard a bus.
Vanya seeks to meet Marcus secretly and discuss a way out of their differences. She requests Marcus to hand her their time-traveling briefcase, promising that the Umbrella Academy would leave the sparrows if Marcus did so. She adds that she has destroyed the world twice and would not advise the Sparrows to face her again as it would only ruin their reputation. Through the conversation between Vanya and Marcus, Fei and her raven seem to be eavesdropping, and they report Marcus's meeting to Ben.
Marcus goes to the basement, where she finds Grace, their robotic mom, with the briefcase. There is also a ball of energy in the basement, with no known origin, but obviously connected to the arrival of the Umbrella Academy team. Just like their robotic mom, Marcus is hypnotized and goes on to touch the ball of energy. The ball expands and explodes, sending an invisible shockwave across the city and disintegrating Marcus completely.