It's a non-pink sequel to a pink film (Oh! Invisible Man). Dunno why. It's barely distinguishable from its predecessor in almost every way that matters, mind you... but it has almost no nudity. The Invisible Girl isn't played by a porn star, but by Asuka Kishi (a model, actress and TV personality who does nothing racier than bikini photoshoots). In one shot, you can see the top her character's supposedly not wearing.
Our "hero" from last time, Touru, is now middle-aged with two adult daughters. He's played by Kazuki Iio. This makes his invisible lechery even more uncomfortable and unpleasant to watch, but fortunately again there's only one sequence of it.
His older daughter, Michiru (i.e. Asuka Kishi) has inherited Dad's superpower... but she hasn't realised yet. She will, though. If she eats salted salmon roe, she'll turn invisible. This might sound like sleaze squared, but in fact it's a sleaze-killer. Michiru's a good girl and she doesn't abuse her invisibility, beyond innocently exploring her interest in an ambiguously dodgy boy (played by Yoshikazu Kotani). Mind you, a misjudgement on her part nearly gets him dumped by his furious girlfriend. (Invisibility wears off at the worst moments.)
I wasn't particularly interested in Michiru. She's cute, but I found something faintly unlikeable about Kishi in the role. She's also less important than you'd think, almost playing second fiddle to her father.
As for Dad, his job involves getting photographic evidence of spousal misdeeds. Charming line of work he's found. This includes such "crimes" as being a man who likes wearing a bra and fishnets. The film's villains have invented a serum that turns men into camp homosexual cross-dressers! If this film had been made in the 1970s, we'd still be throwing rotten vegetables at it today.
Every so often, though, the film throws in a scene that feels improvised. These were my favourite bits. Dad and his younger daughter, Yumi, for instance, had a naturalism that had me wondering if some of their scenes were unscripted. There's also another such scene with Dad, his boss and a transvestite getting drunk together.
1. Clothes and other objects don't turn invisible, so Touru and Michiru have to strip... but it's okay to leave on spectacles. They'll turn invisible with you.
2. The film's almost better for manservice than fanservice. Yoshikazu Kotani gets a lingering shower scene, because Michiru's sneaked in to spy on him.
3. Kotani's playing the most interesting character, actually. He's a flashy, gaudy skirt-chaser who's also capable of being a white knight when he feels like it. His relationship with women and fidelity is unclear. He also seems to enjoy being trodden on. (That's not metaphorical. There's a scene of him lying on a bed with a woman grinding her foot into his back.) Unfortunately he ends up being less important than you'd think and we don't even learn what happens to him.
4. Mitsuko Hoshi's back from the first film (hurrah!), but in a nothing role.
This is an uneven film. It's a comedy and it does indeed have the odd funny scene or moment, but it's also got regrettable stuff like Dad abusing his invisibility to play unpleasant pranks on the women in his office. Michiru is either gullible or stupid when being scouted in the street. The whole "cross-dressing serum" thing works better than you'd think, through sheer shameless brazenness, but it's still eye-rolling and capable of being offensive. (The gay sexual assault scene is Not Good.) Personally, I see no reason to watch this film. It's below-average even for the pink film industry, despite the odd decent joke and some good family chemistry between Dad and his daughters. Even sleaze-hunters will be disappointed.