One of the burning questions for many Pokémon fans picking up Pokémon: Let's Go! on Switch will be how they can acquire one of the franchise's most famous monsters in the game: the mysterious Mew.
Nintendo has been quite sneaky with this, as it has essentially locked Mew behind a paywall - to get the monster, you have to buy a Poké Ball Plus accessory.
Unlocking Mew in the game is easy; simply connect the Poké Ball Plus as a controller and open the in-game menu with the 'B' button. Navigate to Communication and then Mystery Gift. You should see an option that says 'Get with a Poké Ball Plus'. Select this, and the game will download your Mew from the Poké Ball Plus into your main game (you'll need internet access to do this).
There's something to note here; Mew can only be downloaded from the Poké Ball Plus once. If you borrow a friend's Poké Ball Plus or buy one second-hand - and Mew has already been downloaded from said device - then you won't be able to get the monster. Be wary of purchasing Poké Ball Plus accessories that have been opened and used with the game already, or are being sold second-hand. This is effectively like a DLC code included with a boxed game; it's a one-use deal.
Compare that to amiibo, which have similar content-unlocking qualities but can be used as many times as you like and it's rather annoying, but understandable; if Mew could be unlocked multiple times using the same Poké Ball Plus, players could 'farm' the character and trade it with other people.
Please note that you will not be able to bring a Mew caught in Pokémon GO into Pokémon: Let's Go, Pikachu! and Pokémon: Let's Go, Eevee! The ability to claim your gift of Mew may be discontinued at some point after the initial sales period of the Poké Ball Plus.
So there you have it; that's currently the only way that you can obtain Mew in the game. It's worth noting that you can also obtain Mystery Gifts via codes or even the internet, so Nintendo may choose to make Mew available via other means in the future.