#please happen

Obvious answer is it’s something to do with his parents and the way they died. We know they’re dead, we know they died when Lockwood was young, and we know Lockwood won’t move from the house because it’s the last tie he has to his parents, so we can assume he had a relatively happy childhood and good memories with them. 

I expect the forbidden room is either a bedroom or some large storage room, because that’s where (the show heavily implies) Lockwood gets the necklace he gives to Lucy. The necklace Lockwood says used to belong to “someone special to him”. 

Two problems for the parent theory here: 1) why would Lockwood call his mom (or dad, dads can have necklaces, too) “someone special”? Lucy knows they’re dead already and she knows they lived in this house. If the necklace came from one of his parents, why wouldn’t Lockwood just tell Lucy that? 

2) If the room behind the forbidden door is a bedroom, I don’t think it’s the master bedroom. Because, in the first episode during Lucy’s tour of the house, Lockwood says Lucy can use the bathroom in the attic or share the one on the landing with George. Not with Lockwood and George. So, Lockwood’s bedroom most likely has an ensuite, which leads me to believe it’s the master bedroom. 

Another thing I noticed about the house is the number of bedrooms. We have two bedrooms in 35 Portland Row for sure (George’s and Lockwood’s). I predict the room behind the locked door is or can be used as a bedroom, because the house has been able to function without it available in the years since it’s been locked. So, three bedrooms, and Lucy’s room in the attic. Lucy’s room in the attic which Lockwood specifically told Lucy he used to sleep in when he was little. 

Why would Lockwood’s parents make him sleep in the attic as a child when there was at least one, and were possibly two, free bedrooms in the house? A kind uncle who liked to hunt was discussed during Lucy’s interview, so it’s possible he lived with the Lockwoods, or visited often enough that they kept a nice guest room for him. But that still leaves one room in the house that, if not already a bedroom, could function as one. Why would you send your young son to sleep in the attic is there’s an empty room in the house? 

Because, dear reader, there wasn’t an empty room in the house. 

The room belonged to Lockwood’s older sibling.  

An older sister probably, because of the necklace from “someone special” and, of course, Lockwood and George’s discussion about girls and baths in episode two. After George finds Lucy in the bath with her clothes on, Lockwood tells George “Girls are weird about baths,” or something like that. Why would he say that? Why is that what Lockwood chooses to add to the conversation? Could be about his mom, I guess, but if we believe the master bedroom has an ensuite, she and Lockwood never shared a bathroom. Plus, Lockwood said ‘girls’, not ‘women’. If Lockwood has never lived anywhere but Portland Row, what would he know about living with girls? About sharing bathrooms with girls? 

Unless, of course, he had an older sister. 

like just imagine him at the front of camp stumbling in with his guitar case and suitcase and everyone just stares at him, then Val walks up to him and says “your Ricky bowen correct?” he nods his head “im Val your camp counselor, welcome to camp shallow!”