It's a light-hearted bit of fun with Marulk, the long-suffering lackey and toy of the sadistic and possibly evil Ozen. She's always made him wear a female maid outfit, but he's too modest to complain.
EPISODE 1 = Ozen's drunk and Marulk's trying to get her to bed. Unfortunately, Ozen's tall and sinister, while Marulk's a small child. Winches, ropes, heave!
EPISODE 2 = Ozen gives Marulk an unintelligible map and tells him to go there or be punished. Marulk does his best. Surprisingly, this appears to be on the surface, with sun and blue sky. I thought Ozen and Marulk lived down in the Seeker Camp on the 2nd layer of the Abyss?
Anyway, Marulk meets a pure-minded boy called Nat who doesn't realise that Marulk's male. It's all innocent, though.
EPISODE 3 = Ozen tells Marulk to tidy up the bedrooms of Yelme, Zapo and Simred. (We're back in the Seeker Camp, incidentally.) He finds various things there, none of them conducive to clean living. Amusingly, Marulk regards these untidy bedrooms as a worse pit of hell than the actual Abyss he lives in.
EPISODE 4 = is very different. It's how Marulk met Ozen. He's hiding in a cupboard and watches his father get eaten. Ozen's... well, she's Ozen, but Marulk would definitely have died if she hadn't shown up. It's nice, in its own way.
It looks as lovely and imaginative as ever with Made in Abyss, e.g. jumping on the bedroom branches in ep.3, plus of course the beautiful surface world in ep.2. It's a fun micro-series, gently amusing and full of the show's usual charm. You'll enjoy it. There's no trauma here. (Well, ish. Ep.4 definitely isn't one of Marulk's better days, but it's still the story of a good thing happening. You might not show that episode to small children, but that's true of Made in Abyss in general.)