The unnamed family is Boy and Girl's family and the main characters of Boy Girl Dog Cat Mouse Cheese. They are a blended family whose origins wildly differ for each member. They live in an unnamed residence.
Members
| Boy | Girl | ||
| Dog | Cat | ||
| Mouse | Cheese | ||
| Dad | Sarah |
History
Not much is known about the family's history, but Cheese's siblings mention that she was raised by a cow (because cheese comes from milk which comes from cows). The description of the episode "Wedgie" says that she was created in a "lab accident" (the actual episode doesn't elaborate on this so this episode description is a misleading source); and in "Don't Have a Cow" she grows attached to a cow.
Boy and Girl's sides of the family merged when the kids' unnamed father and Sarah, the kids' mother, got married. "Begins!" reveals that both sides lived in separate houses until their parents got married (well, Sarah's side is the very house Boy and Girl live in to this day):
Their origins
One regular day at the house (well, filled with failed high-fives on Boy's side) was turned into the biggest and worst day of their lives as Max and Sarah came home revealing that they're getting married to a person they introduced them to earlier on. Boy's side of the house is rather tidy and kept clean, which isn't replicated on Girl's side of the house. Here, you'd expect chaos 24/7.
The picnic and further meetings
Soon, Sarah and Max brought their kids to the picnic. Once they left, the kids started to socialize, but everything started to turn all the way sideways as Mouse started to eat cheese... in front of the talking limburger cheese named Cheese. Things got pretty chaotic...
Once Boy's side of the family formally met Girl's, the parents had a Bird spouse, named Carlota, in the house. Boy decided to shake things up a bit by making Girl "fart" in front of the very very very fancy woman. Yep, they're still not on good terms.
The wedding: Take One
When the time came the wedding, the kids were made the flower kids. Order came to shove and resulted in a brief scuffle, which then resulted in Cheese-on-Cat and Mouse-on-Dog racing to the altar and resulting in damage to wedding the area.
Now it's time for them to make the cake... easier said than done, really, with them current state of their relationship, pulling pranks on each other. The parents checked in to see the current state of things and Carlota walked out.
A tear in the relationship
The parents noticed that the kids were indeed fighting; in fact, each side mutually hated each other, even to the point that the parents called off the wedding - a decision the kids liked. It would be two weeks before they saw each other again... In the interim, both parents were down in the dumps and the kids were happy. Sarah was making Max hedges and Mouse got Max new friends. Well, not really, as he only just told him that he towed Max's car.
An unlikely pairing
The kids would eventually come face-to-face with each other at Uncle Bob's, where Boy struggles to thank Girl for giving him a tasty suggestion and Girl struggles to welcome him for it, Mouse fixes up Cheese's phone, and Cat impresses Dog with her ability to scare off parrots. ...That parrot was Carlota's.
The kids are able to use their respective abilities to help get Carlota's parrot back to her; Girl has Dog smell the scent, Mouse leads Cat up a tree, Boy saves Cat, and Cheese uses Boy's noise machine to help track the parrot!
New friends, new lives
With the parrot saved, Girl compliments Boy's skills, telling him and his family that they just got off on the wrong side of the foot and that they're indeed cool. They decide to hang out with each other, and it turns out that they do get along with each other! With the wedding now underway, Girl dubs the family "Boy Girl Dog Cat Mouse Cheese" - a name that'll stand the test of time, surely! Oh, and Boy finally sticks the high-five - with Girl! The very person he initially hated but now are best friends - AND step-siblings!
Now that they're best buds, they're finally able to work together on setting up the wedding. The parents are finally married due to the kids' help!
Ages
It is known that Cheese is the youngest member of the family. Keeping this in mind, and knowing that Boy and Girl are both teenagers (Girl is 14, and we don't know how old Boy is other than the fact that he's teenaged), we can apply this assumption to Mouse, Dog and Cat and that they're all around the same age or slightly older or younger. However, things are currently at an unknown and this is an assumption.
In said episode, the birth order seems to be, according to Boy's single-file line order and considering that Cheese is the youngest, we don't know Boy's age (he might be older or younger than Girl), and Girl is fourteen:
Cheese / Cat / Mouse / Dog / Boy / Girl
In "Begins!", it's revealed that the family was conjoined when their parents got married, so they could all share the same ages.