Multi-millionaire Phillip Drummond, who has agreed to the death-bed wish of his housekeeper to raise her two small sons as his own, welcomes 8-year-old Arnold and 12-year-old Willis into his lavish penthouse. Anxious to make them feel at home, he showers them with gifts and love -- and is puzzled when he learns that the boys are planning to sneak from the lap of luxury back to Harlem. Aiding Drummond in his effort to make the street-wise, ghetto youngsters feel welcome in the affluent white world are Drummond's new housekeeper Mrs. Garrett and his 13-year-old daughter Kimberly.

Arnold's eavesdropping leads to trouble when a misunderstanding causes Willis and him to think that Mr. Drummond no longer wants them around; he has heard Drummond tell a social worker that ""black children belong with black families.""

Mr. Drummond's socialite and rather snobbish mother arrives and finds there's a lot she doesn't like about her son's new sons, but she soon learns a valuable lesson about what's really important in a person.

When Mr. Drummond tries to get Arnold and Willis into an exclusive prep school, it turns out to be just a little too exclusive for everyone's tastes.

Arnold ignores warnings and continues to drop water balloons from the balcony. Mr. Drummond's decision to punish Arnold for the prank with a spanking becomes a learning lesson for Willis too, when he insists that he be the one to spank Arnold -- but where's Arnold?

When Arnold loses his favorite doll, he makes sure that his misery is shared equally by the various members of his household, who soon try everything to get it back.

When Arnold is in trouble for putting his goldfish in Mr. Drummond's hot tub, Willis insists that it is wrong to convict him without a trial. The whole family, with Mrs. Garrett as judge, comes up with an important verdict.

Mr. Drummond and family gather around their Christmas tree and recall the many humorous incidents that the family has shared since Arnold and Willis moved in. This special one-hour episode features highlights from previous shows.

Mr. Drummond and family gather around their Christmas tree and recall the many humorous incidents that the family has shared since Arnold and Willis moved in. This special one-hour episode features highlights from previous shows.

Willis puts Arnold in training to fight the local bully, but Mr. Drummond insists more civilized solutions be employed.

Willis invites his neighborhood club from Harlem to visit, but things get out of hand when he tries to impress them with his new wealth.

Mr. Drummond's intention to marry an attractive widow doesn't meet with his children's approval, and Arnold, Willis and Kimberly devise a scheme they hope will turn his ""romantic"" proposal into a disaster.

A lonely Arnold comes up with a method of gaining his family's attention. Unfortunately his plan works a little too well; he ends up with everyone's attention, including the family doctor.

LaWanda Page guest stars as a cousin of Willis and Arnold who, after seeing the boys in their comfortable new surroundings, knows she should stay closer to her long-lost little relatives.

Drummond hires a tutor for Willis and Arnold who does practically everything but teach.

The kids devise a scheme hoping to make Arnold convince the new landlord to let the family keep the penthouse.

To get rid of his pesky little brother, Willis divides the bedroom in half and spends more time at his friend's house.

When Mrs. Garrett decides her life as a housekeeper is unfulfilling, she ends up being a guest in the Drummond home, and then makes an important decision concerning the future.

In order to earn the money to buy disco skates, and to prove a point to Mr. Drummond, Willis gets a job...but is fired on his first working day.

The stars of "Diff'rent Strokes" and "Hello, Larry" get together in a special, hilarious hour in which Phillip Drummond realizes that the purchase of a Portland radio station could mean the loss of a job for his old friend Larry Alder.

The crossover continues on Hello, Larry S01E10 The Trip (II).

The stars of "Diff'rent Strokes" and "Hello, Larry" get together in a special, hilarious hour in which Phillip Drummond realizes that the purchase of a Portland radio station could mean the loss of a job for his old friend Larry Alder.

**Part two originally aired as an episode of "Hello, Larry".

When Arnold is witness to a hold up, the robber tries to ensure that the youngster will not identify him.

Willis is hurt when he thinks his family has forgotten his upcoming birthday. After dropping several unsubtle hints he discovers that not only has everyone remembered, but also his fondest wish has been granted -- a birthday party in his old Harlem neighborhood.

Mrs. Garrett visits Kimberly's school and takes on its pushy principal with surprising results.

Arnold has appendicitis and Drummond has to deal with the bigotry of Fred Tanner, a potential housing project investor whose daughter is the key to getting Arnold to sit still for the operation.

Arnold's life is endangered when the kids find out they can't share a room in the hospital and run away on the eve of Arnold's surgery.

Arnold's well-intentioned endorsement of Larry Alder's hosting talents to a New York TV big-wig gives Larry the opportunity of a lifetime and brings the family to the big apple. Larry's try-out as a New York television talk-show house may be doomed from the start, one disaster follows another and not everyone on the Alder team may be rooting for him to win the job.

The crossover continues on Hello, Larry S02E01 Feudin' and Fussin' (II).

Arnold's well-intentioned endorsement of Larry Alder's hosting talents to a New York TV big-wig gives Larry the opportunity of a lifetime and brings the family to the big apple. Larry's try-out as a New York television talk-show house may be doomed from the start, one disaster follows another and not everyone on the Alder team may be rooting for him to win the job.

**Part two originally aired as an episode of "Hello, Larry".

The Drummond household's curiosity over Mrs. Garrett's new beau turns first to surprise and then to alarm. Mrs. Garrett is in a dither over her first date with Leon, especially when it is followed by a very important question.

Willis' fishy version of the facts of life leaves Arnold with misconceptions and Mr. Drummond on tender hooks. Arnold repeats his ""knowledge"" to a neighbor's daughter, but the girl's mother is not amused.

Arnold's wildest dream is realized when he comes face-to-knee with ""The Champ"" -- special guest star Muhammad Ali. When the meeting arranged by Mr. Drummond between Arnold and his idol, Muhammad Ali, falls through, Kimberly and Willis concoct a wild scheme to insure that Arnold's dream will come true.

The Drummond family celebrates the day Arnold and Willis are supposed to be officially adopted until the visit of a ""relative"" leaves their plans in jeopardy. Whitman Mayo guest stars as Jethro Simpson, who sees his way to go from junk to jewels in a last will and testament leaving a fortune to Willis and Arnold.

It appears that Mr. Drummond's attempts to adopt Arnold and Willis will be aborted by a conniving junk dealer until the boys take matters into their own hands. Whitman Mayo guest stars as ""long-lost relative"" Jethro Simpson who has arrived with a letter supposedly written by the boys' father, leaving Arnold and Willis in his custody.

Willis' cut-throat competitiveness with another boy at his gym leads him to a decision that he will very much regret, especially after it hurts Mr. Drummond and gives Arnold the right to say ""I told you so."" Baseball great Reggie Jackson makes his acting debut playing a key, but unsuspecting role in Willis' questionable scheme.

The Alders and the Drummonds are together again in New York, and Arnold, Willis and Kimberly plan a second Thanksgiving feast with friends Diane and Ruthie. But even the huge Drummond penthouse isn't big enough to hold the exploding tempers that threaten Phil and Larry's long-standing relationship, on a special one-hour episode featuring the stars of "Hello, Larry." Morgan and all the kids get caught up in the feud when Larry learns friendship doesn't necessarily make for good business.

The crossover continues on Hello, Larry S02E10 Thanksgiving Crossover (II).

The Alders and the Drummonds are together again in New York, and Arnold, Willis and Kimberly plan a second Thanksgiving feast with friends Diane and Ruthie. But even the huge Drummond penthouse isn't big enough to hold the exploding tempers that threaten Phil and Larry's long-standing relationship, on a special one-hour episode featuring the stars of "Hello, Larry." Morgan and all the kids get caught up in the feud when Larry learns friendship doesn't necessarily make for good business.

**Part two originally aired as an episode of "Hello, Larry".

Arnold and Willis' relationship is threatened when a fickle female classmate, the object of Arnold's affection, turns her attention toward Willis. Arnold's first love is also his first lesson in jealously as he competes with Willis for the same girl.

Discovered in the wrong place at the wrong time, Willis and Arnold become prime suspects when their neighbor's apartment is robbed and they're caught with one of the stolen items. Mr. Drummond is convinced of his sons' innocence even though Willis' fingerprints are all over the place.

Arnold saves a dog's life, is bitten and then the dog is needed to save Arnold. The Drummond household members frantically search for the ungrateful canine, while Arnold faces a series of rabies shots or death.

Drummond puts his convictions on the line to run for city council, and rooting him on are Arnold, Willis, Kimberly, and an ""unexpected"" new addition to the household. Nedra Volz plays Adelaide Brubaker, the small but sassy housekeeper who helps Drummond mobilize the family for a ""win.""

Mr. Drummond is in ""double-trouble"" when Willis and Arnold decide to get him a date. Feeling a little lonely, Drummond tells the kids what he needs is a little companionship, so they decide to call a computer dating service.

A crucially important business deal keeps Mr. Drummond on edge and Arnold and Willis wondering whether they pack for a California vacation or move back to Harlem.

Willis and Arnold scheme to make extra ""dough"" by selling brownies, only to discover they can't stand the heat of big business and may soon have to get out of the kitchen.

The ""Gooch"" is back and this time he's terrorizing Arnold, but Arnold plans to be ready when the bully strikes. In building Arnold's confidence, Willis convinces him that his martial arts lesson has given him a ""killer"" foot.

Arnold and Willis are trapped in the basement and while they await rescue they reminisce about their recent past...both the good times and the bad. Arnold insists he must wear his Superman outfit to the family's Valentine's Day trip to the circus; the resultant search leads to the basement and a locked door. This show highlights some of the best moments from the past episodes.

Kimberly's new beau, Roger, suggests pairing his sister with Willis for a double-date, until he finds out the color of his true love's brother. When Kimberly discovers her new friend is a bigot, her face burns red and then a far darker shade.

Parent-teacher night leads Mr. Drummond to a romance with Arnold's teacher and poor Arnold to the jealousy of his classmates. Arnold tries every trick in the book to win back his classmates, including one which may have him expelled.

Leaving Willis in charge of the house for Kimberly's slumber party is a mistake Mr. Drummond soon regrets as the ensuing chaos disrupts his own date with a lovely lady. The Facts of Life stars Mindy Cohn, Kim Fields, Julie Anne Haddock, and Molly Ringwald guest star.

Arnold fears that his loved ones are checking out of his life when he stumbles upon Drummond's will and then uncovers the fact that his goldfish has given up the ghost.

Willis seeks comradeship as a member of the Tarantulas, a street gang, but finds only deceit as he gets caught in a web of misplace loyalties. Willis allows himself to be arrested rather than ""squeal"" on his fellow-gang members by telling the truth.

Their family and friends assembled, Phillip and Maggie meet at the altar, only to realize each has made a major mistake, in the concluding part of a special two-part story. Charlotte Rae, Dody Goodman, Janet Jackson and Nedra Volz, each of who had appeared in recurring roles on ""Diff'rent Strokes,"" return as their original characters for the Drummond nuptials.