The latest Professor Layton game opens with its most compelling mystery. Young Katrielle Layton endures a dream where she chases after her father, who vanishes into a dense London fog. Is Professor Hershel Layton, the didactic but likeable star of every other Layton game up to this point, in fact a deadbeat dad? Or is his disappearance itself a mystery?

Having hooked us with that question, Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy takes considerable time before even coming close to answering it. The game instead ushers us into the chipper little detective agency run by Katrielle. Her first client is a talking dog with amnesia, but our heroine sets his case aside as she recruits him, names him Sherl, and sets off to solve other mysteries with her eager assistant Ernest Greeves. They investigate everything from missing pets to the theft of Big Ben's hour hand, and the solutions are rarely less absurd than the alleged crimes.

Katrielle might favor short cases instead of her father's longer story arcs, but Layton's Mystery Journey still adopts the series staples of pointing and clicking. Poking around scenery prompts new clues and conversations, and everyone, from passing joggers to London politicians, has a puzzle or two for Katrielle and her companions to solve.

It's very easy to like Katrielle and her retinue. She's an affable heroine with a breezy wit and sleuthing instincts so sharp we can only assume she's deliberately and politely ignoring Ernest's blatant crush on her. Ernest makes for an endearing sidekick beyond that, and Sherl offers gruff running commentator for their quirks and deductions. Their only shortcomings rise in bantering a little too much. The game is heavy on tutorials at first, and even after that's settled the characters explain the same things over and over. Perhaps, in trying to evoke a quaint London setting, Layton's Mystery Journey embodies those classic 19th century authors who were paid by the word, line break, or apostrophe.

Katrielle's investigations don't lack in colorful characters, be they a pair of gushing lovebird tourists, a conflicted director and his irascible editor, or a snooty recurring rival profiler. Yet there's an undercurrent of blandness in many of the cases. Though they're not without their surprises, the Layton games never had the knife-edge legal melodrama of the Phoenix Wright series or the morbid, bizarre premises of Danganronpa and Zero Escape. While some surprising turns appear later in the game, the early cases in Layton's Mystery Journey suffer pat solutions. The player doesn't even assemble the answers most of the time; even if you've figured out the case, you'll need to wait for Katrielle and her crew to spell it out.

Layton games revolve around their puzzles, of course, and so every case here brings up at a dozen or more traditional blends of logic and trick questions. One might have you swap cows and aliens until everyone's happy, another might merely ask how many times you have to touch a clock to set a certain time. The most enjoyable puzzles tend to be the easier ones. Shuffling pearls from one seashell to another isn't a taxing IQ test, yet it's a fun break from prodding around hotel lobbies and mansion corridors.

When Layton's Mystery Journey gets tough, however, it gets worse. The majority of the more difficult puzzles are such only because they're either poorly explained or oddly strict, and the hints, purchased with coins hidden throughout the backgrounds, aren't much help. For example, one quiz presents you with half a dozen letters and asks you to “represent a kiss.” While there are multiple ways to do this, the game demands a specific arrangement. True, a good logic puzzle requires you to get into the questioner's head, but too often we're tested only on how well we can interpret obtusely explained restrictions. There's no room for creativity in Layton's Mystery Journey.

Even so, the superficial charms pave over many of the annoyances. While the game is clearly a 3DS title in its layout (and you'll see it on the handheld in October), it looks good and plays with sure-footed style on Android and iOS devices. Characters have exaggerated touches, backgrounds benefit from subtle 3-D effects, and the cutscenes are always pleasant, even as you're forced to rotate your phone to see them properly. The music and voice acting are competent, and the localization delights in awful puns and overcooked accents.

The greatest problem in Layton's Mystery Journey may be its refusal to advance by any great leaps. A new protagonist presents the chance for new venues and play mechanics, but Katrielle walks her father's path too often—though at least she does it with a talking dog at her side. Yet it's hard to keep an eager detective like Katrielle down, and her story rises above mediocrity not so much on the puzzles as it does on the mysteries that loom before her. The payoff might not always satisfy, but it keeps you guessing along the way.