Putting it Together is the result of numerous requests for an "update" of Stephen Sondheim's popular compilation show from 1976, Side by Side by Sondheim. Sondheim had long resisted updating that show by interpolating new material, but was finally persuaded by producer Cameron Mackintosh (who produced the original Side by Side by Sondheim, as well as the 1987 London production of Follies) to consider putting together some kind of "sequel" compilation. They brought in Julia McKenzie, who was one of the original creators and stars of the 1976 Side by Side by Sondheim, and was appearing in that 1987 Follies

Sondheim's songs tend to be so situation and character specific, that to do them out of context requires tedious narration and exposition. They had gotten around that difficulty in the original by having a narrator on stage. For this effort, all the creators agreed that they didn't want to do a Side By Side II, keeping the straight revue-with-narrator format of the original. They hit on the idea of creating a dramatic framework to hang the songs on - essentially creating enough of a "context" so that narration would not be necessary. Even though that context wouldn't necessarily mirror the situation of the original show, it would still allow the audience to experience the songs as part of a dramatic whole. This "evening at a dinner party" framework was never intended to be a fully realized dramatic book. The audience would always be aware that it was just a device to string together an evening of Sondheim songs.

The rough "plot" that ensues is a dinner party given by "Paul" (Stephen Collins) and "Amy" (Diana Rigg/Julie Andrews), a couple celebrating their 25th wedding anniversary. Michael Rupert is a party guest, a young colleague from "Paul's" publishing firm. Rachel York is a maid hired for the evening at the beginning, turning into a party guest later in the show. Christopher Durang is a "mischievous and somewhat mysterious uninvited guest" who occasionally comments on the action throughout the evening.

The show begins out of frame, with Chris singing an updated version of the "Invocation and Instructions to the Audience". Actually, he never does get to the "Invocation" - originally written for A Funny Thing Happened On The Way To The Forum, and later put into The Frogs. Rather, he does a version of the "Instructions to the "Audience" portion added for The Frogs, and segues into a customized "Putting it Together" with the company. After that, everyone drops into character, and the cocktail party begins with the guests arriving. During the course of the evening, all 3 men - particularly "Paul" Stephen and "Guest" Michael - flirt with and compete for "Maid/Guest" Rachel, to the annoyance of "Amy" Julie and amusement of "Mysterious Guest" Christopher Durang. Michael eventually prevails, disappearing upstairs with Rachel, as Julie vents her anger at Stephen and Act I ends.

Act II begins with an "out of character" opener, "Back In Business", from Dick Tracy. They drop back into character, several hours later - after dinner and somewhat drunk. Chris talks the others into participating in strange party games, which basically serve as a cheap way to pull in out of context songs while somewhat developing their characters. Julie and Stephen more or less reconcile, and Michael and Rachel make genuine connection as the show ends. Such is the "plot".