Strap in, buckaroos, this is another completely bonkers one.
Brogan’s childhood pal Murph turns up unexpectedly, crashes on the sofa, borrows Brogan’s car, etc. etc. Brogan, meanwhile, is busy investigating the theft of the titular beetle, a specimen of an endangered species which turns from a beetle into a butterfly (yes really) and which secretes a chemical in its womb (yes, really) that can help regenerate amputated limbs. `All those people involved with this series, and apparently not a single one was at school the day that science class covered insects.
Shortly after the audience (but not Brogan) learns that Murph is the one that stole the beetle, Brogan’s car blows up, apparently killing Murph, and two thugs burgle Brogan’s flat, failing to acquire the beetle but traumatising young Matt, who happens to be home. As if his sister and mother having PTSD wasn’t enough.
Young Matt then acquires a gun from somewhere, and we get a weirdly pro-gun message for a British show (even one two years pre-Dunblaine) as both of Matt’s parents tell him that they understand he was just doing it to protect the family and they love him, rather than adding “…but statistically guns in the household lead to increased rates of homicide and suicide, and this is clearly just a trauma response on your part, so maybe go learn karate or something instead.” Presumably they were still hoping to sell the series to the American market, though I’m not sure how well a series encouraging teenage boys to tool up would have gone down there either.
Anyway, it turns out Murph isn’t dead, of course, and Brogan has to face the truth about his pal, and it all gets resolved with everybody apparently forgetting about the beetle, which quietly turns into a butterfly and sods off.
The B plot this episode has Castle and Took breaking up a barroom brawl and arresting the main perp, only to discover that he’s a sportsball star so the entire precinct are willing to give him a free pass even though he’s plainly guilty. The twist is that he then gets arrested for domestic violence and all the cops who’d supported him turn against him, which I suppose ties in nicely with the Brogan/Murph plot about having to acknowledge that someone you like isn’t very nice, and it’s good to have an anti-DV message in a story like this, but still.
There’s also a subplot involving young Matt acquiring a tarantula, which I think was meant to tie into the beetle plot (maybe the thugs mistake the tarantula for the beetle? IDK) but just sort of fizzles out and suggests the story needed another editing pass.
Oh, and the Brogans’ animatronic pet is <shudder> back, though it doesn’t do very much.
Trivia point: when I searched for “The Forever Beetle” on YouTube, the third result down was the official video for “Penny Lane”.